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  • Problems Mapping a List of Serializable Objets with JDO

    - by Sergio del Amo
    I have two classes Invoice and InvoiceItem. I would like Invoice to have a List of InvoiceItem Objets. I have red that the list must be of primitive or serializable objects. I have made InvoiceItem Serializable. Invoice.java looks like import java.util.ArrayList; import java.util.Date; import java.util.List; import javax.jdo.annotations.Column; import javax.jdo.annotations.Embedded; import javax.jdo.annotations.EmbeddedOnly; import javax.jdo.annotations.IdGeneratorStrategy; import javax.jdo.annotations.IdentityType; import javax.jdo.annotations.PersistenceCapable; import javax.jdo.annotations.Persistent; import javax.jdo.annotations.Element; import javax.jdo.annotations.PrimaryKey; import com.google.appengine.api.datastore.Key; import com.softamo.pelicamo.shared.InvoiceCompanyDTO; @PersistenceCapable(identityType = IdentityType.APPLICATION) public class Invoice { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String number; @Persistent private Date date; @Persistent private List<InvoiceItem> items = new ArrayList<InvoiceItem>(); public Invoice() {} public Long getId() { return id; } public void setId(Long id) {this.id = id;} public String getNumber() { return number;} public void setNumber(String invoiceNumber) { this.number = invoiceNumber;} public Date getDate() { return date;} public void setDate(Date invoiceDate) { this.date = invoiceDate;} public List<InvoiceItem> getItems() { return items;} public void setItems(List<InvoiceItem> items) { this.items = items;} } and InvoiceItem.java looks like import java.io.Serializable; import java.math.BigDecimal; import javax.jdo.annotations.PersistenceCapable; import javax.jdo.annotations.Persistent; @PersistenceCapable public class InvoiceItem implements Serializable { @Persistent private BigDecimal amount; @Persistent private float quantity; public InvoiceItem() {} public BigDecimal getAmount() { return amount;} public void setAmount(BigDecimal amount) { this.amount = amount;} public float getQuantity() { return quantity;} public void setQuantity(float quantity) { this.quantity = quantity;} } I get the next error while running a JUnit test. javax.jdo.JDOUserException: Attempt to handle persistence for object using datastore-identity yet StoreManager for this datastore doesn't support that identity type at org.datanucleus.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:375) at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:674) at org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:694) at com.softamo.pelicamo.server.InvoiceStore.add(InvoiceStore.java:23) at com.softamo.pelicamo.server.PopulateStorage.storeInvoices(PopulateStorage.java:58) at com.softamo.pelicamo.server.PopulateStorage.run(PopulateStorage.java:46) at com.softamo.pelicamo.server.InvoiceStoreTest.setUp(InvoiceStoreTest.java:44) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) NestedThrowablesStackTrace: Attempt to handle persistence for object using datastore-identity yet StoreManager for this datastore doesn't support that identity type org.datanucleus.exceptions.NucleusUserException: Attempt to handle persistence for object using datastore-identity yet StoreManager for this datastore doesn't support that identity type at org.datanucleus.state.AbstractStateManager.<init>(AbstractStateManager.java:128) at org.datanucleus.state.JDOStateManagerImpl.<init>(JDOStateManagerImpl.java:215) at org.datanucleus.jdo.JDOAdapter.newStateManager(JDOAdapter.java:119) at org.datanucleus.state.StateManagerFactory.newStateManagerForPersistentNew(StateManagerFactory.java:150) at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1297) at org.datanucleus.sco.SCOUtils.validateObjectForWriting(SCOUtils.java:1476) at org.datanucleus.store.mapped.scostore.ElementContainerStore.validateElementForWriting(ElementContainerStore.java:380) at org.datanucleus.store.mapped.scostore.FKListStore.validateElementForWriting(FKListStore.java:609) at org.datanucleus.store.mapped.scostore.FKListStore.internalAdd(FKListStore.java:344) at org.datanucleus.store.appengine.DatastoreFKListStore.internalAdd(DatastoreFKListStore.java:146) at org.datanucleus.store.mapped.scostore.AbstractListStore.addAll(AbstractListStore.java:128) at org.datanucleus.store.mapped.mapping.CollectionMapping.postInsert(CollectionMapping.java:157) at org.datanucleus.store.appengine.DatastoreRelationFieldManager.runPostInsertMappingCallbacks(DatastoreRelationFieldManager.java:216) at org.datanucleus.store.appengine.DatastoreRelationFieldManager.access$200(DatastoreRelationFieldManager.java:47) at org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.apply(DatastoreRelationFieldManager.java:115) at org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations(DatastoreRelationFieldManager.java:80) at org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations(DatastoreFieldManager.java:955) at org.datanucleus.store.appengine.DatastorePersistenceHandler.storeRelations(DatastorePersistenceHandler.java:527) at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess(DatastorePersistenceHandler.java:299) at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects(DatastorePersistenceHandler.java:251) at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:235) at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:3185) at org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:3161) at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1298) at org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1175) at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:669) at org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:694) at com.softamo.pelicamo.server.InvoiceStore.add(InvoiceStore.java:23) at com.softamo.pelicamo.server.PopulateStorage.storeInvoices(PopulateStorage.java:58) at com.softamo.pelicamo.server.PopulateStorage.run(PopulateStorage.java:46) at com.softamo.pelicamo.server.InvoiceStoreTest.setUp(InvoiceStoreTest.java:44) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Moreover, when I try to store an invoice with a list of items through my app. In the development console I can see that items are not persisted to any field while the rest of the invoice class properties are stored properly. Does anyone know what I am doing wrong? Solution As pointed in the answers, the error says that the InvoiceItem class was missing a primaryKey. I tried with: @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; But I was getting javax.jdo.JDOFatalUserException: Error in meta-data for InvoiceItem.id: Cannot have a java.lang.Long primary key and be a child object (owning field is Invoice.items). In persist list of objets, @aldrin pointed that For child classes the primary key has to be a com.google.appengine.api.datastore.Key value (or encoded as a string) see So, I tried with Key. It worked. @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key id;

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  • Log4j: Issues about the FallbackErrorHandler

    - by rdogpink
    I am working on a client-server-application and wanted to implement a flexible Loggingframework, so I chose log4j, which doesn´t really evolve anymore, but it is still handy framework. Because the Logging happens along the network, i wanted a solution for the case, that the network drive isn´t available, so the Logger has to change its destination file(s). Now I wanted to use the FallbackErrorHandler (configured with a XML-File) from the Log4j-library and the implementation worked: When my network drive isn´t available, it switches to a local Logfile, so no logging should be lost. But I headded two problems since yesterday and couldn´t figure or find out, how to solve it. No return to initial Logging Configuration: When the network drive is on again and the Logger could write to the old destinations, log4j still logs at the local drive and I can´t figure out, how to notify the original (primary) Logger to start again. I also tried to attach a second Appender to the ErrorHandler, which should mirror the failed primary Logger, that it tries to write on the network destination and when the network is on again, it logs in both files, on the local and on the network drive. But unfortunately it didn´t work out, I only got a failure message that the ErrorHandler-content doesn´t fit. log4j:WARN The content of element type "errorHandler" must match "(param*,root-ref?,logger-ref*,appender-ref?)". This is the responsible code. <appender name="TraceAppender" class="org.apache.log4j.DailyRollingFileAppender"> <!-- The second appender-ref "TestAppender" leads to the error. --> <errorHandler class="org.apache.log4j.varia.FallbackErrorHandler"> <logger-ref ref="com.idoh"/> <appender-ref ref="TraceFallbackAppender"/> <appender-ref ref="TestAppender"/> </errorHandler> <param name="datePattern" value=".yyyy-MM-dd" /> <param name="file" value="logs/Trace.txt" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%-6r %d{HH:mm:ss,SSS} [%t] %-5p - %m%n"/> </layout> </appender> So, how could I trigger log4j to reset to initial configuration or hold a second appender parallel to the "Local-Logger". My Application should work by itself and shouldn´t have to be restarted often. First Error message is swallowed: I recognized, that the first message, which leads to the switching between the primary logger and the FallbackErrorHandler (for example a logging-request to a readonly-File), is swallowed, so neither the primary logger logs it (because it can´t) nor the backup-Logger knows what it missed. So anybody else ran in this problem and could solve it? Or has any suggestions?

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  • Ubuntu 12.04 KVM running Ubuntu 12.04 with linux-image-virtual crash on boot

    - by D.Mill
    One of my VMs is stuck on "pause" in virsh. If I destroy and restart it, it will go to pause after a bit of time as "running". I can at best enter my username at login if I'm quick but it'll then shutdown. I don't know where to start with this so any help would be great!! I can access the VMs files via guestfish. the kern.log and syslog don't populate new lines. This is the last input I get from kern.log: Dec 13 11:21:08 soft201 kernel: imklog 5.8.6, log source = /proc/kmsg started. Dec 13 11:21:08 soft201 kernel: [ 0.000000] Initializing cgroup subsys cpuset Dec 13 11:21:08 soft201 kernel: [ 0.000000] Initializing cgroup subsys cpu Dec 13 11:21:08 soft201 kernel: [ 0.000000] Linux version 3.2.0-34-virtual (buildd@allspice) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #53-Ubuntu SMP Thu Nov 15 11:08:40 UTC 2012 (Ubuntu 3.2.0-34.53-virtual 3.2.33) Dec 13 11:21:08 soft201 kernel: [ 0.000000] Command line: root=UUID=61d48b48-a06a-48fb-842e-b38014086a93 ro quiet splash Dec 13 11:21:08 soft201 kernel: [ 0.000000] KERNEL supported cpus: Dec 13 11:21:08 soft201 kernel: [ 0.000000] Intel GenuineIntel Dec 13 11:21:08 soft201 kernel: [ 0.000000] AMD AuthenticAMD Dec 13 11:21:08 soft201 kernel: [ 0.000000] Centaur CentaurHauls Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-provided physical RAM map: Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 0000000000100000 - 00000000dfffc000 (usable) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000dfffc000 - 00000000e0000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000feffc000 - 00000000ff000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 0000000100000000 - 0000000a20000000 (usable) Dec 13 11:21:08 soft201 kernel: [ 0.000000] NX (Execute Disable) protection: active Dec 13 11:21:08 soft201 kernel: [ 0.000000] DMI 2.4 present. Dec 13 11:21:08 soft201 kernel: [ 0.000000] DMI: Bochs Bochs, BIOS Bochs 01/01/2007 Dec 13 11:21:08 soft201 kernel: [ 0.000000] e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] e820 remove range: 00000000000a0000 - 0000000000100000 (usable) Dec 13 As you can see the last line gets cut off. I don't even know if this is that relevant. dmesg logs are empty. The qemu log for the VM returns this: 2012-12-13 12:29:47.584+0000: starting up LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-1.0 -enable-kvm -m 40960 -smp 14,sockets=14,cores=1,threads=1 -name numerink201 -uuid f4a889ed-a089-05d0-cc9d-9825ab1faeba -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/numerink201.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -drive file=/var/lib/libvirt/images/client.soft.fr/tmpcZAD9U.qcow2,if=none,id=drive-ide0-0-0,format=qcow2 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -fsdev local,security_model=none,id=fsdev-fs0,path=/home/shared_folders/soft201 -device virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=hostshare,bus=pci.0,addr=0x5 -netdev tap,fd=18,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=02:00:00:1d:b9:e7,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 char device redirected to /dev/pts/3 qemu: terminating on signal 15 from pid 28248 2012-12-13 12:30:14.455+0000: shutting down I've added more logging, libvirt.log gives me this: 2012-12-13 13:24:38.525+0000: 27694: info : libvirt version: 0.9.8 2012-12-13 13:24:38.525+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:38.525+0000: 27694: warning : qemuCapsInit:856 : Failed to get host power management capabilities 2012-12-13 13:24:39.865+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:39.865+0000: 27694: warning : lxcCapsInit:77 : Failed to get host power management capabilities 2012-12-13 13:24:39.866+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:39.866+0000: 27694: warning : umlCapsInit:87 : Failed to get host power management capabilities I don't really know where to go from here. I'll post whatever info you require

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  • My computer freezes irregurarly

    - by Manhim
    My computer started to freeze at irregular times for 3 weeks now. What happens My computer freezes, the video stops. (No graphic glitches, it just stops) Sound keeps playing up to some time (Usually 10-30 seconds) then stops playing. Sometimes, randomly, the screen on my G-15 keyboard flickers and I see caracters not at the right places. Usually happens for about 1-2 seconds and a bit before my computer freezes. I have to keep the power button pressed for 4 seconds to shut my computer down. I still hear my hard drives and fans working. Sometimes it works with no problems for a full day, some other times it just keeps freezing each time I restart my computer and I have to leave it for the rest of the day. Sometimes my mouse freezes for a fraction of a second (Like 0.01 to 0.2 seconds) quite randomly, usually before it freezes. No errors spotted by the "Action center" unlike when I had problems with my last video card on this system (Driver errors). My G-15 LCD screen also freezes. What I did so far I have had similar problems in the past and I had changed my hard drive (It was faulty), so I tested my software RAID-0 array and it was faulty so I changed it. (I reinstalled Windows 7 with this part). I also tested with unplugging my secondary hard drive. My CPU was running at about 100 degree Celsius, I removed the dust between the fans and the heatsink and it's now between 50-60. I ran a CPU stress-test and it didn't freeze during the tests (using Prime95 on all cores) Ran a memory test (using memtest86+) for a single pass and there were no errors. Ran a GPU stress test with ati-tools and furmark and it didn't freeze during the tests. (No artefacts either) I had troubles with my graphic card when I got it, but I think that it got fixed with a driver update. I checked the voltages in my BIOS setup and they all seemed ok (±0.2 I think). I have ran on the computer without problems with Fedora 15 on an external hard drive (Appart that it couldn't load Gnome 3 and was reverting to Gnome 2, didn't want to install drivers since I use it on multiple computers) I used it to backup my files from the raid array to my 1TB hard drive for the reinstallation of Windows. (So the crashes only happenned on Windows) [The external hard drive is plugged directly on a SATA port] I contacted EVGA (My graphic card vendor) and pointed them on this question, I'm looking for an answer. Ran sensors on Fedora 15 and got this output: http://pastebin.com/0BHJnAvu When it happens When I play video games (Mostly) When I play flash games (Second most) When I'm looking at my desktop background (It rarely happens when I have a window open, but it does, sometimes) Specs Windows Seven x64 Home Premium Motherboard: M2N-SLI Deluxe CPU: AMD Phenom 9950 x2 @ 2.6GHz Memory: Kingston 4x2GB Dual Channel (Pretty basic memory sticks) Hard drives: Was 2x250GB (Western digital caviar) in raid-0 + 1TB (WD caviar black), I replaced the raid array with a 750GB (WD caviar black) [Yes I removed the array from the raid configurations] 750W Power supply No overcloking. Ever. There have been some power-downs like 4-5 weeks ago, but the problem didn't start immediately after. (I wasn't home, so my computer got shut-down) My current to-try list Change the thermal paste on my CPU. Change my graphic card with a temporary one and stress the computer. Change my power supply. In this situation, how can I successfully pin-point the current hardware problem? (If it's a hardware problem) Because I don't really have the budget to just forget and replace everything. I also don't really have hardware to test-replace current hardware.

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  • File Server - Storage configuration: RAID vs LVM vs ZFS something else... ?

    - by privatehuff
    We are a small company that does video editing, among other things, and need a place to keep backup copies of large media files and make it easy to share them. I've got a box set up with Ubuntu Server and 4 x 500 GB drives. They're currently set up with Samba as four shared folders that Mac/Windows workstations can see fine, but I want a better solution. There are two major reasons for this: 500 GB is not really big enough (some projects are larger) It is cumbersome to manage the current setup, because individual hard drives have different amounts of free space and duplicated data (for backup). It is confusing now and that will only get worse once there are multiple servers. ("the project is on sever2 in share4" etc) So, I need a way to combine hard drives in such a way as to avoid complete data loss with the failure of a single drive, and so users see only a single share on each server. I've done linux software RAID5 and had a bad experience with it, but would try it again. LVM looks ok but it seems like no one uses it. ZFS seems interesting but it is relatively "new". What is the most efficient and least risky way to to combine the hdd's that is convenient for my users? Edit: The Goal here is basically to create servers that contain an arbitrary number of hard drives but limit complexity from an end-user perspective. (i.e. they see one "folder" per server) Backing up data is not an issue here, but how each solution responds to hardware failure is a serious concern. That is why I lump RAID, LVM, ZFS, and who-knows-what together. My prior experience with RAID5 was also on an Ubuntu Server box and there was a tricky and unlikely set of circumstances that led to complete data loss. I could avoid that again but was left with a feeling that I was adding an unnecessary additional point of failure to the system. I haven't used RAID10 but we are on commodity hardware and the most data drives per box is pretty much fixed at 6. We've got a lot of 500 GB drives and 1.5 TB is pretty small. (Still an option for at least one server, however) I have no experience with LVM and have read conflicting reports on how it handles drive failure. If a (non-striped) LVM setup could handle a single drive failing and only loose whichever files had a portion stored on that drive (and stored most files on a single drive only) we could even live with that. But as long as I have to learn something totally new, I may as well go all the way to ZFS. Unlike LVM, though, I would also have to change my operating system (?) so that increases the distance between where I am and where I want to be. I used a version of solaris at uni and wouldn't mind it terribly, though. On the other end on the IT spectrum, I think I may also explore FreeNAS and/or Openfiler, but that doesn't really solve the how-to-combine-drives issue.

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  • Announcing the New Windows Azure Web Sites Shared Scaling Tier

    - by Clint Edmonson
    Windows Azure Web Sites has added a new pricing tier that will solve the #1 blocker for the web development community. The shared tier now supports custom domain names mapped to shared-instance web sites. This post will outline the plan changes and elaborate on how the new pricing model makes Windows Azure Web Sites an even richer option for web development shops of all sizes. Free Shared Reserved # of Sites 10 100 100 Egress 165MB/Day 5GB/Month Included 5GB/Month Included Storage 1GB 1GB 10GB Throttling CPU/Memory/Egress CPU/Memory Unlimited Price Free $.02/hr per site, per instance $.08/hr per core Setting the Stage In June, we released the first public preview of Windows Azure Web Sites, which gave web developers a great platform on which to get web sites running using their web development framework of choice. PHP, Node.js, classic ASP, and ASP.NET developers can all utilize the Windows Azure platform to create and launch their web sites. Likewise, these developers have a series of data storage options using Windows Azure SQL Databases, MySQL, or Windows Azure Storage. The Windows Azure Web Sites free offer enabled startups to get their site up and running on Windows Azure with a minimal investment, and with multiple deployment and continuous integration features such as Git, Team Foundation Services, FTP, and Web Deploy.  The response to the Windows Azure Web Sites offer has been overwhelmingly positive. Since the addition of the service on June 12th, tens of thousands of web sites have been deployed to Windows Azure and the volume of adoption is increasing every week. Preview Feedback In spite of the growth and success of the product, the community has had questions about features lacking in the free preview offer. The main question web developers asked regarding Windows Azure Web Sites relates to the lack of the free offer’s support for domain name mapping. During the preview launch period, customer feedback made it obvious that the lack of domain name mapping support was an area of concern. We’re happy to announce that this #1 request has been delivered as a feature of the new shared plan. New Shared Tier Portal Features In the screen shot below, the “Scale” tab in the portal shows the new tiers – Free, Shared, and Reserved – and gives the user the ability to quickly move any of their free web sites into the shared tier. With a single mouse-click, the user can move their site into the shared tier. Once a site has been moved into the shared tier, a new Manage Domains button appears in the bottom action bar of the Windows Azure Portal giving site owners the ability to manage their domain names for a shared site. This button brings up the domain-management dialog, which can be used to enter in a specific domain name that will be mapped to the Windows Azure Web Site. Shared Tier Benefits Startups and large web agencies will both benefit from this plan change. Here are a few examples of scenarios which fit the new pricing model: Startups no longer have to select the reserved plan to map domain names to their sites. Instead, they can use the free option to develop their sites and choose on a site-by-site basis which sites they elect to move into the shared plan, paying only for the sites that are finished and ready to be domain-mapped Agencies who manage dozens of sites will realize a lower cost of ownership over the long term by moving their sites into reserved mode. Once multi-site companies reach a certain price point in the shared tier, it is much more cost-effective to move sites to a reserved tier.  Long-term, it’s easy to see how the new Windows Azure Web Sites shared pricing tier makes Windows Azure Web Sites it a great choice for both startups and agency customers, as it enables rapid growth and upgrades while keeping the cost to a minimum. Large agencies will be able to have all of their sites in their own instances, and startups will have the capability to scale up to multiple-shared instances for minimal cost and eventually move to reserved instances without worrying about the need to incur continually additional costs. Customers can feel confident they have the power of the Microsoft Windows Azure brand and our world-class support, at prices competitive in the market. Plus, in addition to realizing the cost savings, they’ll have the whole family of Windows Azure features available. Continuous Deployment from GitHub and CodePlex Along with this new announcement are two other exciting new features. I’m proud to announce that web developers can now publish their web sites directly from CodePlex or GitHub.com repositories. Once connections are established between these services and your web sites, Windows Azure will automatically be notified every time a check-in occurs. This will then trigger Windows Azure to pull the source and compile/deploy the new version of your app to your web site automatically. Walk-through videos on how to perform these functions are below: Publishing to an Azure Web Site from CodePlex Publishing to an Azure Web Site from GitHub.com These changes, as well as the enhancements to the reserved plan model, make Windows Azure Web Sites a truly competitive hosting option. It’s never been easier or cheaper for a web developer to get up and running. Check out the free Windows Azure web site offering and see for yourself. Stay tuned to my twitter feed for Windows Azure announcements, updates, and links: @clinted

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  • Booting the liveCD/USB in EFI mode fails on Samsung Tablet XE700T1A

    - by F.L.
    My tablet is Samsung Series 7 Slate (XE700T1A-A02FR (French Language)). It operates an Intel Sandy Bridge architecture. The main issue about this tablet is that it ships with an installed Windows 7 in (U)EFI mode (GPT partition table, etc.), so I'd like to get an EFI dual boot with Ubuntu. But it seems I can't boot on the liveCD in EFI mode. It starts loading (up to initrd), but I then get a blank (black) screen. I've tried the nomodeset kernel option (as well as removing quiet and splash) with no luck. [2012-09-27] I have used the Ubuntu 12.04.1 Desktop ISO (I have read somewhere that it is the only one that can boot in EFI mode). I'd say this has something to do with UEFI since the LiveCD boots in bios mode but not in efi mode. Besides, I am not sure my boot info will help, since I can't boot the LiveCD in EFI mode. As a result I can't install ubuntu in EFI mode. So it would be the boot info from the liveCD boot in bios mode. This happens on a ubuntu-12.04.1-desktop-amd64 iso used on a LiveUSB. Live USB was created by dd'ing the iso onto the full disk device (i.e. /dev/sdx no number) of the Flash drive. I have also tried copying the LiveCD files on a primary GPT partition, but with no luck, I just get the grub shell, no menu, no install option. [2012-09-28] I tried today a flash drive created with Ubuntu's Startup Disk Creator and the alternate 12.04.1 64 bit ISO. I get a grub menu in text mode (which meens it did start in efi mode) with install options / test options. But when I start any of these, I simply get a black screen (no cursor, neither mouse nor text-mode cursor). I tried removing the 'quiet' option and adding nomodeset and acpi=off, but it didn't do any good. So this is the same result as for the LiveCD. [2012-10-01] I have tried with a version of the secure remix version via usb-creator-gtk. The boot on the USB key has the same symptoms. Boot in EFI mode is impossible (I have menu but whatever entry I choose, I get the blank screen problem). The boot in BIOS mode works, I did the install. Then I used boot-repair to try installing grub-efi and get a system that would boot in efi mode. But I can't boot this system, because the EFI firmware doesn't seem to detect that sda contains a valid efi partition. Here is the resulting boot-info Boot info 1253554 [2012-10-01] Today, I have reinstalled the pre-shipped version of windows 7, and then installed ubuntu from a secure-remix iso dumped on USB flash drive vie usb-creator-gtk booted in BIOS mode. When install ended, I said "continue testing" then I used boot-repair to try get the bootloader installed. Now, when I boot the tablet, I get the grub menu, it can chainload windows 7 flawlessly. But when I try to start one of the ubuntu options I get the same old blank screen. Here is the new boot-info: Boot info 1253927 [2012-10-01] I tried installing the 3.3 kernel by chrooting a live usb boot (secure remix again) into the installed system. Same symptoms. I feel the key to this is that the device's efi firmware (which is EFI v2.0) would expose the graphics hardware in a way that prevents the kernel to initialize it, and thus prevents it from booting (the kernel stops all drive access just after the screen turns kind of very dark purple). Here is some info on the UEFI firmware as given by rEFInd: EFI revision: 2.00 Platform: x86_64 (64 bit) Firmware: American Megatrends 4.635 Screen Output: Graphics Output (UEFI), 800x600 [2012-10-08] This week end I tried loading the kernel with elilo. Eventhough I didn't have more luck on booting the kernel, elilo gives more info when loading the kernel. I think the next step is trying to load a kernel with EFI stub directly.

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  • Graphics trouble after resuming from hibernate or suspend

    - by Voyagerfan5761
    I have a Dell Inspiron 2650 (with NVidia graphics, using nouveau drivers) that I'm using to try out Ubuntu. It's all great, except that Hibernate and Suspend aren't usable. Yes, I know that questions about power-save issues are rampant in the Linux support universe, but it seems that every time I find a solution it's for a very specific hardware combination and doesn't apply to me. So anyway, here goes. When I resume from either power-saving mode, I'll get graphics problems anywhere on the range from a few scattered random-colored pixels that won't change; all the way to full-screen patterns that don't change as I move the mouse, hit keys on the keyboard, or even bring up the shutdown dialog using the power button. Those full-screen issues (which may involve stripes with random pixels, partial black screen, or both) always end in me forcing the machine to shut down by holding the power button. I haven't done much testing yet to determine what severity level is most commonly associated with each mode, but I do avoid using either power-save option because of these issues. I'll add info on my hardware as I can gather it (no home internet connection, and this laptop is tethered to my desk by a dead battery and casing degradation). Please feel free to request something specific in the question comments. Hardware Info See this hardinfo report for my system's hardware configuration. (No, my username is not "myuser"; I sanitized hardinfo's output before publishing it.) Screenshots These screenshots are from a relatively mild occurrence, which happened after the second hibernation I took that session. The first one worked great, though I used the wireless card and Firefox heavily between the two hibernation attempts. Take a look at what happened when I opened my home directory in Nautilus and scrolled it: See below for the situations I've tested so far. The real trouble comes when the machine resumes to an unusable state; in such cases I can't even unlock the screen or properly reboot, much less take a screenshot. I have a hunch that putting a CD in the drive will cause such major failures, and I will try that at some point; see related question. Situations Tested Maverick (10.10) Suspend Seems to suspend nicely with nothing running Seems to suspend nicely with flash drive plugged in On resume from suspend with no flash drive, Terminal and gedit running: Funky graphics on top of log output, then blank screen with pixelated cursor; no response to power button (normally will shutdown 60 seconds later) Hibernate Seems to hibernate nicely with nothing running Seems to hibernate nicely with a few apps (Terminal, Mouse preferences) running Seems to not hibernate when flash drive plugged in Seems to not hibernate when System Monitor is running Have encountered failed hibernation (after several hours and one successful hibernate/thaw cycle) with no external media connected and no programs running except normal background stuff Natty LiveCD (11.04_2010-12-22) When I tested it, Natty wouldn't stay logged in. It played part of the login sound and then [ OK ] appeared in the top right corner (white-on-black terminal text) for a few seconds. Then it kicked me back to the Unlock screen. It did that four times before I gave up and just tested suspend from the Unlock screen. Suspend Resumed to vertical gray and black lines 2px (?) wide, then shifted to vertical "jail bars" of black over a black screen with above-described random pixels and mouse pointer. No apparent response to input from mouse (clicking randomly). Keyboard and touchpad unrecognized.

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  • Failed to unmount partitions

    - by msknapp
    I'm trying to install ubuntu from a pen drive. I have windows 7 installed already and want to keep that installation. I have a 3TB drive that has one 2TB partition on it, so the last 1TB is completely unused, which is where I want to install ubuntu. I started ubuntu in "try ubuntu" mode and then opened gparted, and then deleted the unused partition for the last third of my drive, then tried to install ubuntu. During the install, it asked me if I wanted to unmount the drives I already have The installer has detected that the following disks have mounted partitions: /dev/sda, /dev/sdb Do you want the installer to try to unmount the partitions on these disks before continuing? If you leave them mounted, you will not be able to create, delete, or resize partitions on these disks, but you may be able to install to existing partitions there. No, Yes I said no because I don't want to lose my windows 7 installation, nor any of that data. I wonder, if I had said yes above, would I have lost all the data on those drives? Anyways, I hit no and continued. I chose to install ubuntu alongside windows 7, and hit continue. A few minutes passed when this popup appeared: Failed to unmount partitions The installer needs to commit changes to partition tables, but cannot do so because the partitions on the following mount points could not be unmounted: /media/ubuntu/Three\ Terabyte Drive Terabyte\ DriveDrive Please close any applications using these mount points. Would you like the installer to try to unmount these partitions again? Go Back, Continue Why is this not working? What am I supposed to do? ========== Update: I went ahead and said yes, it can unmount those partitions. It finished installing Ubuntu, but now when i start my machine it just takes me to the grub rescue prompt. Seems like it broke something. What can I do now? =============== Results of fdisk -l: Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00027e14 Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 206848 976771071 488282112 7 HPFS/NTFS/exFAT WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders, total 5860533168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 1 4294967295 2147483647+ ee GPT Partition 1 does not start on physical sector boundary. Disk /dev/sdc: 16.0 GB, 16008609792 bytes 255 heads, 63 sectors/track, 1946 cylinders, total 31266816 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdc1 * 32 31266815 15633392 c W95 FAT32 (LBA) Disk /dev/sdd: 999.5 GB, 999501594624 bytes 255 heads, 63 sectors/track, 121515 cylinders, total 1952151552 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0002ae3f Device Boot Start End Blocks Id System /dev/sdd1 2048 1952151551 976074752 7 HPFS/NTFS/exFAT

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  • Data Source Security Part 4

    - by Steve Felts
    So far, I have covered Client Identity and Oracle Proxy Session features, with WLS or database credentials.  This article will cover one more feature, Identify-based pooling.  Then, there is one more topic to cover - how these options play with transactions.Identity-based Connection Pooling An identity based pool creates a heterogeneous pool of connections.  This allows applications to use a JDBC connection with a specific DBMS credential by pooling physical connections with different DBMS credentials.  The DBMS credential is based on either the WebLogic user mapped to a database user or the database user directly, based on the “use database credentials” setting as described earlier. Using this feature enabled with “use database credentials” enabled seems to be what is proposed in the JDBC standard, basically a heterogeneous pool with users specified by getConnection(user, password). The allocation of connections is more complex if Enable Identity Based Connection Pooling attribute is enabled on the data source.  When an application requests a database connection, the WebLogic Server instance selects an existing physical connection or creates a new physical connection with requested DBMS identity. The following section provides information on how heterogeneous connections are created:1. At connection pool initialization, the physical JDBC connections based on the configured or default “initial capacity” are created with the configured default DBMS credential of the data source.2. An application tries to get a connection from a data source.3a. If “use database credentials” is not enabled, the user specified in getConnection is mapped to a DBMS credential, as described earlier.  If the credential map doesn’t have a matching user, the default DBMS credential is used from the datasource descriptor.3b. If “use database credentials” is enabled, the user and password specified in getConnection are used directly.4. The connection pool is searched for a connection with a matching DBMS credential.5. If a match is found, the connection is reserved and returned to the application.6. If no match is found, a connection is created or reused based on the maximum capacity of the pool: - If the maximum capacity has not been reached, a new connection is created with the DBMS credential, reserved, and returned to the application.- If the pool has reached maximum capacity, based on the least recently used (LRU) algorithm, a physical connection is selected from the pool and destroyed. A new connection is created with the DBMS credential, reserved, and returned to the application. It should be clear that finding a matching connection is more expensive than a homogeneous pool.  Destroying a connection and getting a new one is very expensive.  If you can use a normal homogeneous pool or one of the light-weight options (client identity or an Oracle proxy connection), those should be used instead of identity based pooling. Regardless of how physical connections are created, each physical connection in the pool has its own DBMS credential information maintained by the pool. Once a physical connection is reserved by the pool, it does not change its DBMS credential even if the current thread changes its WebLogic user credential and continues to use the same connection. To configure this feature, select Enable Identity Based Connection Pooling.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/EnableIdentityBasedConnectionPooling.html  "Enable identity-based connection pooling for a JDBC data source" in Oracle WebLogic Server Administration Console Help. You must make the following changes to use Logging Last Resource (LLR) transaction optimization with Identity-based Pooling to get around the problem that multiple users will be accessing the associated transaction table.- You must configure a custom schema for LLR using a fully qualified LLR table name. All LLR connections will then use the named schema rather than the default schema when accessing the LLR transaction table.  - Use database specific administration tools to grant permission to access the named LLR table to all users that could access this table via a global transaction. By default, the LLR table is created during boot by the user configured for the connection in the data source. In most cases, the database will only allow access to this user and not allow access to mapped users. Connections within Transactions Now that we have covered the behavior of all of these various options, it’s time to discuss the exception to all of the rules.  When you get a connection within a transaction, it is associated with the transaction context on a particular WLS instance. When getting a connection with a data source configured with non-XA LLR or 1PC (using the JTS driver) with global transactions, the first connection obtained within the transaction is returned on subsequent connection requests regardless of the values of username/password specified and independent of the associated proxy user session, if any. The connection must be shared among all users of the connection when using LLR or 1PC. For XA data sources, the first connection obtained within the global transaction is returned on subsequent connection requests within the application server, regardless of the values of username/password specified and independent of the associated proxy user session, if any.  The connection must be shared among all users of the connection within a global transaction within the application server/JVM.

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  • Moving data files failing

    - by Miles Hayler
    Trying to migrate data from C: to D: via the SBS console is failing. The wizard starts running but drops out in the first few seconds. I'll post the full logs, but the important lines appear to be as follows: An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: GetServerBackupTaskStatus: fail to find the task --- ErrorCode:0 I've been googling for days with no luck. I have found that mscorlib is a component of .net, and I've discovered multiple instances of the file in %windir%, %windir%\winsxs, %windir%\Microsoft.net Anyone come across and fixed this one before? --------------------------------------------------------- [1516] 110315.190856.1105: Storage: Initializing...C:\Program Files\Windows Small Business Server\Bin\MoveData.exe [1516] 110315.190856.2875: Storage: Data Store to be moved: Exchange [1516] 110315.190856.5305: TaskScheduler: Exception System.IO.FileNotFoundException: [1516] 110315.190856.5605: Exception: --------------------------------------- An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Timestamp: 03/15/2011 19:08:56 Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) [1516] 110315.190856.5625: Storage: Exception Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException: [1516] 110315.190856.5635: Exception: --------------------------------------- [b]An exception of type 'Type: Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException, Common, Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' has occurred.[/b] Timestamp: 03/15/2011 19:08:56 Message: Failed to find the task path Stack: at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() --------------------------------------- An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Timestamp: 03/15/2011 19:08:56 Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) [1516] 110315.190856.5665: Storage: Error Retrieving Server Backup Task Status: ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: GetServerBackupTaskStatus: fail to find the task ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException: Failed to find the task path ---> System.IO.FileNotFoundException: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() at Microsoft.WindowsServerSolutions.Storage.MoveData.Helper.get_ServerBackupTaskState() [1516] 110315.190857.6216: Storage: Backup Task State: Unknown [1516] 110315.190857.9347: Storage: Launching the Move Data Wizard! [1516] 110315.190857.9397: Wizard: Admin:QueryNextPage(null) = Storage.MoveDataWizard.GettingStartedPage [1516] 110315.190857.9417: Wizard: TOC Storage.MoveDataWizard.GettingStartedPage is on ExpectedPath [1516] 110315.190857.9577: Wizard: Storage.MoveDataWizard.GettingStartedPage entered [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.GettingStartedPage) = Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190857.9657: Wizard: TOC Storage.MoveDataWizard.DiagnoseDataStorePage is on ExpectedPath [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.DiagnoseDataStorePage) = Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190857.9657: Wizard: TOC Storage.MoveDataWizard.NewDataStoreLocationPage is on ExpectedPath [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.NewDataStoreLocationPage) = null [1516] 110315.190857.9697: Wizard: ---------------------------------- [1516] 110315.190857.9697: Wizard: The pages visted: [1516] 110315.190857.9697: Wizard: Current Page := [TOC Storage.MoveDataWizard.GettingStartedPage] [1516] 110315.190857.9697: Wizard: [TOC] : TOC Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190857.9697: Wizard: [TOC] : TOC Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190857.9697: Wizard: Step 1 of 3 [1516] 110315.190907.0406: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.GettingStartedPage) = Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190907.0416: Wizard: Storage.MoveDataWizard.GettingStartedPage exited with the button: Next [1516] 110315.190907.0416: WizardChainEngine Next Clicked: Going to page {0}.: Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190907.0496: Wizard: Storage.MoveDataWizard.DiagnoseDataStorePage entered [1516] 110315.190907.0606: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.DiagnoseDataStorePage) = Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190907.0606: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.NewDataStoreLocationPage) = null [1516] 110315.190907.0606: Wizard: ---------------------------------- [1516] 110315.190907.0606: Wizard: The pages visted: [1516] 110315.190907.0606: Wizard: [TOC] visited: TOC Storage.MoveDataWizard.GettingStartedPage [1516] 110315.190907.0606: Wizard: Current Page := [TOC Storage.MoveDataWizard.DiagnoseDataStorePage] [1516] 110315.190907.0616: Wizard: [TOC] : TOC Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190907.0616: Wizard: Step 2 of 3 [19772] 110315.190907.0656: Storage: Starting System Diagnosis [19772] 110315.190907.0656: Storage: Getting Data Store Information [19772] 110315.190907.1086: Storage: Create the list of storage and DB directory path [19772] 110315.190907.1246: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks..ctor [19772] 110315.190907.1546: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.Initialize [19772] 110315.190907.1596: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190907.1606: Messaging: Exchange install path: C:\Program Files\Microsoft\Exchange Server\bin [19772] 110315.190908.4157: Messaging: E12 Monad runspace created ID: Microsoft.PowerShell [19772] 110315.190908.4237: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190908.4287: Messaging: Executed management shell command: get-exchangeserver [19772] 110315.190910.2369: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190910.2369: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190910.5699: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.GatherAdminInfo [19772] 110315.190910.5699: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190910.5719: Messaging: Executed management shell command: get-user -Identity "dmagroup.local\Administrator" [19772] 110315.190911.0870: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.0880: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.0880: Messaging: Executed management shell command: get-mailbox -Identity "d2ae2bf0-48a7-4ce9-9e72-bb3c765454ac" [19772] 110315.190911.1300: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1310: Messaging: User Administrator is mail enabled and can use MessagingManagement to send mail. [19772] 110315.190911.1310: Messaging: Email address used for user: [email protected] [19772] 110315.190911.1440: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1440: Messaging: Executed management shell command: get-group -Identity "Domain Admins" [19772] 110315.190911.1630: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1640: Messaging: User Administrator is a member of Domain Admins and can use MessagingManagement to manage Exchange. [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.GatherAdminInfo [19772] 110315.190911.1640: Messaging: MessagingManagement enabled for Exchange management: True [19772] 110315.190911.1640: Messaging: MessagingManagement enabled for mail submission: True [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.Initialize [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Tasks.TaskMoveExchangeData.CreateDataStoreDriveList [19772] 110315.190911.1670: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.1670: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1670: Messaging: Executed management shell command: get-storagegroup -Server "SERVER01" [19772] 110315.190911.2990: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.3070: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.3070: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.3070: Messaging: Executed management shell command: get-mailboxdatabase -Server "SERVER01" [19772] 110315.190911.4440: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.4520: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.4520: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.4520: Messaging: Executed management shell command: get-publicfolderdatabase -Server "SERVER01" [19772] 110315.190911.5240: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.5510: Storage: Data Store Drive/s Details:Name=C:\,Size=12675712420 [19772] 110315.190911.5510: Storage: Data Store Size Details: Current Total Size=12675712420 Required Size=12675712420 [19772] 110315.190911.5510: Storage: MoveData Task can move the Data Store=True [19772] 110315.190911.8401: Storage: An error was encountered when performing system diagnosis : ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: WMI error occurred while accessing drive ---> System.Management.ManagementException: Not found at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode) at System.Management.ManagementObjectCollection.ManagementObjectEnumerator.MoveNext() at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) at Microsoft.WindowsServerSolutions.Storage.Common.DataStoreInfo.LoadAvailableDrives() at Microsoft.WindowsServerSolutions.Storage.Common.MoveDataUtil.CanMoveData(DataStoreInfo storeInfo, MoveDataError& error) at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.DiagnoseDataStore(Object sender, DoWorkEventArgs args) [1516] 110315.190912.0331: Storage: An error occured during the execution: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: Diagnosing the Data Store failed (see the inner exception) ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: WMI error occurred while accessing drive ---> System.Management.ManagementException: Not found at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode) at System.Management.ManagementObjectCollection.ManagementObjectEnumerator.MoveNext() at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) at Microsoft.WindowsServerSolutions.Storage.Common.DataStoreInfo.LoadAvailableDrives() at Microsoft.WindowsServerSolutions.Storage.Common.MoveDataUtil.CanMoveData(DataStoreInfo storeInfo, MoveDataError& error) at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.DiagnoseDataStore(Object sender, DoWorkEventArgs args) at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.backgroundWorker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e) --- End of inner exception stack trace --- at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Delegate.DynamicInvokeImpl(Object[] args) at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbacks() at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at Microsoft.WindowsServerSolutions.Common.Wizards.Framework.WizardFrameView.Create() at Microsoft.WindowsServerSolutions.Common.Wizards.Framework.WizardChainEngine.Launch() at Microsoft.WindowsServerSolutions.Storage.MoveData.MainClass.LaunchMoveDataWizard() at Microsoft.WindowsServerSolutions.Storage.MoveData.MainClass.Main(String[] args)

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  • WNetAddConnection2 in Windows 7 with Impersonation and no Error Code

    - by Adam Driscoll
    I'm doing some crazy impersonation stuff to get around UAC dialogs in Windows 7 so the user does not have to interact with the UI (I have the admin creds of course). I have a process running as the Administrator and elevated past UAC. The issue that I'm facing is that when I make a call to WNetAddConnection2, within this process, I am not getting a new mapped net drive. The function returns ERROR_SUCCESS but no net drive is visible. We have another method of adding network drives using 'subst' but this, again, returns successful does does not add a net drive. I have tried to use the default user (which is the Administrator because of process's security context) and I have tried using specific user credentials. I can map the drive just fine through Explorer. Of course the same functionality works fine in XP/2003. I haven't got around to testing on Vista because of issues with impersonation that are limiting my ability to spin up the process. Are there unique Windows 7 limits on this function? MSDN does not glean any that I can find. Any help would be greatly appreciated!

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  • Give back full control to a user on a disk from another computer

    - by Foghorn
    I have my friend's hard drive mounted externally. After messing with the permissions with TAKEOWN so I could fix some viruses, I have full control over their drive. The problem is, now it's stuck in a "autochk not found" reboot sequence. I think the problem is that the boot sector is invisible to the drive now. So my question is, How can I use icacls to give back the full ownership, when the user I am giving it to is not on my machine? I ran the TAKEOWN command from my windows 7 laptop, their machine is a windows xp Professional with three partitions, I only altered the one that has the boot sector. Here is the permissions that icacls shows: (Where my computer is %System% my username is ME, and the drive is E:\ C:\Users\ME icacls E:\* E:\$RECYCLE.BIN %System%\ME:(OI)(CI)(F) Mandatory Label\Low Mandatory Level:(OI)(CI)(IO)(NW) E:\ALLDATAW %System%\ME:(I)(OI)(CI)(F) E:\alrt_200.data %System%\ME:(OI)(CI)(F) E:\AUTOEXEC.BAT %System%\ME:(OI)(CI)(F) E:\AZ Commercial %System%\ME:(I)(OI)(CI)(F) E:\boot.ini %System%\ME:(OI)(CI)(F) E:\Config.Msi %System%\ME:(I)(OI)(CI)(F) E:\CONFIG.SYS %System%\ME:(OI)(CI)(F) E:\Documents and Settings %System%\ME:(I)(OI)(CI)(F) E:\IO.SYS %System%\ME:(OI)(CI)(F) E:\Mitchell1 %System%\ME:(I)(OI)(CI)(F) E:\MSDOS.SYS %System%\ME:(OI)(CI)(F) E:\MSOCache %System%\ME:(I)(OI)(CI)(F) E:\NTDClient.log %System%\ME:(OI)(CI)(F) E:\NTDETECT.COM %System%\ME:(OI)(CI)(F) E:\ntldr %System%\ME:(OI)(CI)(F) E:\pagefile.sys %System%\ME:(OI)(CI)(F) E:\Program Files %System%\ME:(I)(OI)(CI)(F) E:\RECYCLER %System%\ME:(I)(OI)(CI)(F) E:\RHDSetup.log %System%\ME:(OI)(CI)(F) E:\System Volume Information %System%\ME:(I)(OI)(CI)(F) E:\WINDOWS %System%\ME:(I)(OI)(CI)(F) Successfully processed 22 files; Failed processing 0 files C:\Users\ME

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  • What strategy do you use to sync your code when working from home

    - by Ben Daniel
    At my work I currently have my development environment inside a Virtual Machine. When I need to do work from home I copy my VM and any databases I need onto a laptop drive sized external USB drive. After about 10 minutes of copying I put the drive in my pocket and head home, copy back the VM and databases onto my personal computer and I'm ready to work. I follow the same steps to take the work back with me. So if I count the total amount of time I spend waiting around for files to finish copying in order for me to take work home and bring it back again, it comes to around 40 minutes! I do have a VPN connection to my work from home (providing the internet is up at both sites) and a decent internet speed (8mbits down/?up) but I find Remote Desktoping into my work machine laggy enough for me to want to work on my VM directly. So in looking at what other options I have or how I could improve my existing option I'm interested in what strategy you use or recommend to do work at home and keeping your code/environment in sync. EDIT: I'd prefer an option where I don't have to commit my changes into version control before I leave work - as I like to make meaningful descriptive comments in my commits, committing would take longer than just copying my VM onto a portable drive! lol Also I'd prefer a solution where my dev environment stays in sync too. Having said that I'm still very interested in your own solutions even if they don't exactly solve my problem as best as I'd like. :)

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  • TFS Folders - Getting them to work like Subversion "Trunk/Tags/Branches"

    - by Sam Schutte
    I recently started using Team Foundation Server, and am having some trouble getting it to work the way I want it to. I've used Subversion for a couple years now, and love the way it works. I always set up three folders under each project, Trunk, Tags, and Branches. When I'm working on a project, all my code lives under a folder called "C:\dev\projectname". This "projectname" folder can be made to point to either trunk, or any of the branches or tags using Subversion (with the switch command). Now that I'm using TFS (my client's system), I'd like things to work the same way. I created a "Trunk" folder with my project in it, and mapped "Project/Trunk/Website" to "c:\dev\Website". Now, I want to make a release under the "tags" folder (located in "Project/Tags/Version 1.0/Website", and TFS is giving me the following error when I execute the branch command: "No appropriate mapping exists for $Project/tags/Version 1.0/Website" From what I can find on the internet, TFS expects you to have a mapping to your hard drive at the root of the project (the "Project" folder in my case), and then have all the source code that lives in trunk, tags and branches all pulled down to your hard drive. This sucks because it requires way too much stuff on your hard drive, and even worse, when you are working in a solution in Visual Studio, you won't be able to pull down "Version 2.0" and have all your project references to other projects work, because they'll all be pointing to "trunk" folders under the main folder, not just the main folder itself. What I want to do is have the root "Project/Website" folder on my hard drive, and be able to have it point to (mapped to) either tags, branches, or trunk, depending on what i'm doing, without having to screw around with fixing Visual Studio project references. Ideas?

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  • static variable lose its value

    - by user542719
    I have helper class with this static variable that is used for passing data between two classes. public class Helper{ public static String paramDriveMod;//this is the static variable in first calss } this variable is used in following second class mathod public void USB_HandleMessage(char []USB_RXBuffer){ int type=USB_RXBuffer[2]; MESSAGES ms=MESSAGES.values()[type]; switch(ms) { case READ_PARAMETER_VALUE: // read parameter values switch(prm){ case PARAMETER_DRIVE_MODE: // paramet drive mode Helper.paramDriveMod =(Integer.toString(((USB_RXBuffer[4]<< 8)&0xff00))); System.out.println(Helper.paramDriveMod+"drive mode is selectd ");//here it shows the value that I need. ..........}}//let say end switch and method and the following is an third class method use the above class method public void buttonSwitch(int value) throws InterruptedException{ boolean bool=true; int c=0; int delay=(int) Math.random(); while(bool){ int param=3; PARAMETERS prm=PARAMETERS.values()[param]; switch(value){ case 0: value=1; while(c<5){ Thread.sleep(delay); protocol.onSending(3,prm.PARAMETER_DRIVE_MODE.ordinal(),dataToRead,dataToRead.length);//read drive mode System.out.println(Helper.paramDriveMod+" drive mode is ..........in wile loop");//here it shows null value }}//let say end switch and method what is the reason that this variable lose its value?

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  • Apache console accesses network drives, service does not?

    - by danspants
    I have an apache 2.2 server running Django. We have a network drive T: which we need constant access to within our Django app. When running Apache as a service, we cannot access this drive, as far as any django code is concerned the drive does not exist. If I add... <Directory "t:/"> Options Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> to the httpd.conf file the service no longer runs, but I can start apache as a console and it works fine, Django can find the network drive and all is well. Why is there a difference between the console and the service? Should there be a difference? I have the service using my own log on so in theory it should have the same access as I do. I'm keen to keep it running as a service as it's far less obtrusive when I'm working on the server (unless there's a way to hide the console?). Any help would be most appreciated.

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  • Is it possible to have WAMP run httpd.exe as user [myself] instead of local SYSTEM?

    - by Olivier H
    Hello! I run a django application over apache with mod_wsgi, using WAMP. A certain URL allows me to stream the content of image files, the paths of which are stored in database. The files can be located whether on local machine or under network drive (\my\network\folder). With the development server (manage.py runserver), I have no trouble at all reading and streaming the files. With WAMP, and with network drive files, I get a IOError : obviously because the httpd instance does not have read permission on said drive. In the task manager, I see that httpd.exe is run by SYSTEM. I would like to tell WAMP to run the server as [myself] as I have read and write permissions on the shared folder. (eventually, the production server should be run by a 'www-admin' user having the permissions) Mapping the network shared folder on a drive letter (Z: for instance) does not solve this at all. The User/Group directives in httpd.conf do not seem to have any kind of influence on Apache's behaviour. I've also regedited : I tried to duplicate the HKLM[...]\wampapache registry key under HK_CURRENT_USER\ and rename the original key, but then the new key does not seem to be found when I cmd this > httpd.exe -n wampapache -k start or when I run WAMP. I've run out of ideas :) Has anybody ever had the same issue?

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  • Parsing Windows Event Logs, is it possible?

    - by xceph
    Hello, I am doing a little research into the feasibility of a project I have in mind. It involves doing a little forensic work on images of hard drives, and I have been looking for information on how to analyze saved windows event log files. I do not require the ability to monitor current events, I simply want to be able to view events which have been created, and record the time and application/process which created those events. However I do not have much experience in the inner workings of the windows system specifics, and am wondering if this is possible? The plan is to create images of a hard drive, and then do the analysis on a second machine. Ideally this would be done in either Java or Python, as they are my most proficient languages. The main concerns I have are as follows: Is this information encrypted in anyway? Are there any existing API for parsing this data directly? Is there information available regarding the format in which these logs are stored, and how does it differ from windows versions? This must be possible from analyzing the drive itself, as ideally the installation of windows on the drive would not be running, (as it would be a mounted image on another system) The closest thing I could find in my searches is http://www.j-interop.org/ but that seems to be aimed at remote clients. Ideally nothing would have to be installed on the imaged drive. The other solution which seemed to also pop up is the JNI library, but that also seems to be more so in the area of monitoring a running system. Any help at all is greatly appreciated. :)

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  • Install Ubuntu Netbook Edition with Wubi Installer

    - by Matthew Guay
    Ubuntu is one of the most popular versions of Linux, and their Netbook Remix edition is especially attractive for netbook owners.  Here we’ll look at how you can easily try out Ubuntu on your netbook without a CD/DVD drive. Netbooks, along with the growing number of thin, full powered laptops, lack a CD/DVD drive.  Installing software isn’t much of a problem since most programs, whether free or for-pay, are available for download.  Operating systems, however, are usually installed from a disk.  You can easily install Windows 7 from a flash drive with our tutorial, but installing Ubuntu from a USB flash drive is more complicated.  However, using Wubi, a Windows installer for Ubuntu, you can easily install it directly on your netbook and even uninstall it with only a few clicks. Getting Started Download and run the Wubi installer for Ubuntu (link below).  In the installer, select the drive you where you wish to install Ubuntu, the size of the installation (this is the amount dedicated to Ubuntu; under 20Gb should be fine), language, username, and desired password.  Also, from the Desktop environment menu, select Ubuntu Netbook to install the netbook edition.  Click Install when your settings are correct. Wubi will automatically download the selected version of Ubuntu and install it on your computer. Windows Firewall may ask if you want to unblock Wubi; select your network and click Allow access. The download will take around an hour on broadband, depending on your internet connection speed.  Once the download is completed, it will automatically install to your computer.  If you’d prefer to have everything downloaded before you start the install, download the ISO of Ubuntu Netbook edition (link below) and save it in the same folder as Wubi. Then, when you run Wubi, select the netbook edition as before and click Install.  Wubi will verify that your download is valid, and will then proceed to install from the downloaded ISO.  This install will only take about 10 minutes. Once the install is finished you will be asked to reboot your computer.  Save anything else you’re working on, and then reboot to finish setting up Ubuntu on your netbook. When your computer reboots, select Ubuntu at the boot screen.  Wubi leaves the default OS as Windows 7, so if you don’t select anything it will boot into Windows 7 after a few seconds. Ubuntu will automatically finish the install when you boot into it the first time.  This took about 12 minutes in our test. When the setup is finished, your netbook will reboot one more time.  Remember again to select Ubuntu at the boot screen.  You’ll then see a second boot screen; press your Enter key to select the default.   Ubuntu only took less than a minute to boot in our test.  When you see the login screen, select your name and enter your password you setup in Wubi.  Now you’re ready to start exploring Ubuntu Netbook Remix. Using Ubuntu Netbook Remix Ubuntu Netbook Remix offers a simple, full-screen interface to take the best advantage of netbooks’ small screens.  Pre-installed applications are displayed in the application launcher, and are organized by category.  Click once to open an application. The first screen on the application launcher shows your favorite programs.  If you’d like to add another application to the favorites pane, click the plus sign beside its icon. Your files from Windows are still accessible from Ubuntu Netbook Remix.  From the home screen, select Files & Folders on the left menu, and then click the icon that says something like 100GB Filesystem under the Volumes section. Now you’ll be able to see all of your files from Windows.  Your user files such as documents, music, and pictures should be located in Documents and Settings in a folder with your user name. You can also easily install a variety of free applications via the Software Installer. Connecting to the internet is also easy, as Ubuntu Netbook Remix automatically recognized the WiFi adaptor on our test netbook, a Samsung N150.  To connect to a wireless network, click the wireless icon on the top right of the screen and select the network’s name from the list. And, if you’d like to customize your screen, right-click on the application launcher and select Change desktop background. Choose a background picture you’d like. Now you’ll see it through your application launcher.  Nice! Most applications are opened full-screen.  You can close them by clicking the x on the right of the program’s name. You can also switch to other applications from their icons on the top left.  Open the home screen by clicking the Ubuntu logo in the far left. Changing Boot Options By default, Wubi will leave Windows as the default operating system, and will give you 10 seconds at boot to choose to boot into Ubuntu.  To change this, boot into Windows and enter Advanced system settings in your start menu search. In this dialog, click Settings under Startup and Recovery. From this dialog, you can select the default operating system and the time to display list of operating systems.  You can enter a lower number to make the boot screen appear for less time. And if you’d rather make Ubuntu the default operating system, select it from the drop-down list.   Uninstalling Ubuntu Netbook Remix If you decide you don’t want to keep Ubuntu Netbook Remix on your computer, you can uninstall it just like you uninstall any normal application.  Boot your computer into Windows, open Control Panel, click Uninstall a Program, and enter ubuntu in the search box.  Select it, and click Uninstall. Click Uninstall at the prompt.  Ubuntu uninstalls very quickly, and removes the entry from the bootloader as well, so your computer is just like it was before you installed it.   Conclusion Ubuntu Netbook Remix offers an attractive Linux interface for netbooks.  We enjoyed trying it out, and found it much more user-friendly than most Linux distros.  And with the Wubi installer, you can install it risk-free and try it out on your netbook.  Or, if you’d like to try out another alternate netbook operating system, check out our article on Jolicloud, another new OS for netbooks. Links Download Wubi Installer for Windows Download Ubuntu Netbook Edition Similar Articles Productive Geek Tips Easily Install Ubuntu Linux with Windows Using the Wubi InstallerInstall VMware Tools on Ubuntu Edgy EftHow to install Spotify in Ubuntu 9.10 using WineInstalling PHP5 and Apache on UbuntuInstalling PHP4 and Apache on Ubuntu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips VMware Workstation 7 Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Explorer++ is a Worthy Windows Explorer Alternative Error Goblin Explains Windows Error Codes Twelve must-have Google Chrome plugins Cool Looking Skins for Windows Media Player 12 Move the Mouse Pointer With Your Face Movement Using eViacam Boot Windows Faster With Boot Performance Diagnostics

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  • How to Tell a Hardware Problem From a Software Problem

    - by Chris Hoffman
    Your computer seems to be malfunctioning — it’s slow, programs are crashing or Windows may be blue-screening. Is your computer’s hardware failing, or does it have a software problem that you can fix on your own? This can actually be a bit tricky to figure out. Hardware problems and software problems can lead to the same symptoms — for example, frequent blue screens of death may be caused by either software or hardware problems. Computer is Slow We’ve all heard the stories — someone’s computer slows down over time because they install too much software that runs at startup or it becomes infected with malware. The person concludes that their computer is slowing down because it’s old, so they replace it. But they’re wrong. If a computer is slowing down, it has a software problem that can be fixed. Hardware problems shouldn’t cause your computer to slow down. There are some rare exceptions to this — perhaps your CPU is overheating and it’s downclocking itself, running slower to stay cooler — but most slowness is caused by software issues. Blue Screens Modern versions of Windows are much more stable than older versions of Windows. When used with reliable hardware with well-programmed drivers, a typical Windows computer shouldn’t blue-screen at all. If you are encountering frequent blue screens of death, there’s a good chance your computer’s hardware is failing. Blue screens could also be caused by badly programmed hardware drivers, however. If you just installed or upgraded hardware drivers and blue screens start, try uninstalling the drivers or using system restore — there may be something wrong with the drivers. If you haven’t done anything with your drivers recently and blue screens start, there’s a very good chance you have a hardware problem. Computer Won’t Boot If your computer won’t boot, you could have either a software problem or a hardware problem. Is Windows attempting to boot and failing part-way through the boot process, or does the computer no longer recognize its hard drive or not power on at all? Consult our guide to troubleshooting boot problems for more information. When Hardware Starts to Fail… Here are some common components that can fail and the problems their failures may cause: Hard Drive: If your hard drive starts failing, files on your hard drive may become corrupted. You may see long delays when you attempt to access files or save to the hard drive. Windows may stop booting entirely. CPU: A failing CPU may result in your computer not booting at all. If the CPU is overheating, your computer may blue-screen when it’s under load — for example, when you’re playing a demanding game or encoding video. RAM: Applications write data to your RAM and use it for short-term storage. If your RAM starts failing, an application may write data to part of the RAM, then later read it back and get an incorrect value. This can result in application crashes, blue screens, and file corruption. Graphics Card: Graphics card problems may result in graphical errors while rendering 3D content or even just while displaying your desktop. If the graphics card is overheating, it may crash your graphics driver or cause your computer to freeze while under load — for example, when playing demanding 3D games. Fans: If any of the fans fail in your computer, components may overheat and you may see the above CPU or graphics card problems. Your computer may also shut itself down abruptly so it doesn’t overheat any further and damage itself. Motherboard: Motherboard problems can be extremely tough to diagnose. You may see occasional blue screens or similar problems. Power Supply: A malfunctioning power supply is also tough to diagnose — it may deliver too much power to a component, damaging it and causing it to malfunction. If the power supply dies completely, your computer won’t power on and nothing will happen when you press the power button. Other common problems — for example, a computer slowing down — are likely to be software problems. It’s also possible that software problems can cause many of the above symptoms — malware that hooks deep into the Windows kernel can cause your computer to blue-screen, for example. The Only Way to Know For Sure We’ve tried to give you some idea of the difference between common software problems and hardware problems with the above examples. But it’s often tough to know for sure, and troubleshooting is usually a trial-and-error process. This is especially true if you have an intermittent problem, such as your computer blue-screening a few times a week. You can try scanning your computer for malware and running System Restore to restore your computer’s system software back to its previous working state, but these aren’t  guaranteed ways to fix software problems. The best way to determine whether the problem you have is a software or hardware one is to bite the bullet and restore your computer’s software back to its default state. That means reinstalling Windows or using the Refresh or reset feature on Windows 8. See whether the problem still persists after you restore its operating system to its default state. If you still see the same problem – for example, if your computer is blue-screening and continues to blue-screen after reinstalling Windows — you know you have a hardware problem and need to have your computer fixed or replaced. If the computer crashes or freezes while reinstalling Windows, you definitely have a hardware problem. Even this isn’t a completely perfect method — for example, you may reinstall Windows and install the same hardware drivers afterwards. If the hardware drivers are badly programmed, the blue-screens may continue. Blue screens of death aren’t as common on Windows these days — if you’re encountering them frequently, you likely have a hardware problem. Most blue screens you encounter will likely be caused by hardware issues. On the other hand, other common complaints like “my computer has slowed down” are easily fixable software problems. When in doubt, back up your files and reinstall Windows. Image Credit: Anders Sandberg on Flickr, comedy_nose on Flickr     

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  • How to Identify Which Hardware Component is Failing in Your Computer

    - by Chris Hoffman
    Concluding that your computer has a hardware problem is just the first step. If you’re dealing with a hardware issue and not a software issue, the next step is determining what hardware problem you’re actually dealing with. If you purchased a laptop or pre-built desktop PC and it’s still under warranty, you don’t need to care about this. Have the manufacturer fix the PC for you — figuring it out is their problem. If you’ve built your own PC or you want to fix a computer that’s out of warranty, this is something you’ll need to do on your own. Blue Screen 101: Search for the Error Message This may seem like obvious advice, but searching for information about a blue screen’s error message can help immensely. Most blue screens of death you’ll encounter on modern versions of Windows will likely be caused by hardware failures. The blue screen of death often displays information about the driver that crashed or the type of error it encountered. For example, let’s say you encounter a blue screen that identified “NV4_disp.dll” as the driver that caused the blue screen. A quick Google search will reveal that this is the driver for NVIDIA graphics cards, so you now have somewhere to start. It’s possible that your graphics card is failing if you encounter such an error message. Check Hard Drive SMART Status Hard drives have a built in S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) feature. The idea is that the hard drive monitors itself and will notice if it starts to fail, providing you with some advance notice before the drive fails completely. This isn’t perfect, so your hard drive may fail even if SMART says everything is okay. If you see any sort of “SMART error” message, your hard drive is failing. You can use SMART analysis tools to view the SMART health status information your hard drives are reporting. Test Your RAM RAM failure can result in a variety of problems. If the computer writes data to RAM and the RAM returns different data because it’s malfunctioning, you may see application crashes, blue screens, and file system corruption. To test your memory and see if it’s working properly, use Windows’ built-in Memory Diagnostic tool. The Memory Diagnostic tool will write data to every sector of your RAM and read it back afterwards, ensuring that all your RAM is working properly. Check Heat Levels How hot is is inside your computer? Overheating can rsult in blue screens, crashes, and abrupt shut downs. Your computer may be overheating because you’re in a very hot location, it’s ventilated poorly, a fan has stopped inside your computer, or it’s full of dust. Your computer monitors its own internal temperatures and you can access this information. It’s generally available in your computer’s BIOS, but you can also view it with system information utilities such as SpeedFan or Speccy. Check your computer’s recommended temperature level and ensure it’s within the appropriate range. If your computer is overheating, you may see problems only when you’re doing something demanding, such as playing a game that stresses your CPU and graphics card. Be sure to keep an eye on how hot your computer gets when it performs these demanding tasks, not only when it’s idle. Stress Test Your CPU You can use a utility like Prime95 to stress test your CPU. Such a utility will fore your computer’s CPU to perform calculations without allowing it to rest, working it hard and generating heat. If your CPU is becoming too hot, you’ll start to see errors or system crashes. Overclockers use Prime95 to stress test their overclock settings — if Prime95 experiences errors, they throttle back on their overclocks to ensure the CPU runs cooler and more stable. It’s a good way to check if your CPU is stable under load. Stress Test Your Graphics Card Your graphics card can also be stress tested. For example, if your graphics driver crashes while playing games, the games themselves crash, or you see odd graphical corruption, you can run a graphics benchmark utility like 3DMark. The benchmark will stress your graphics card and, if it’s overheating or failing under load, you’ll see graphical problems, crashes, or blue screens while running the benchmark. If the benchmark seems to work fine but you have issues playing a certain game, it may just be a problem with that game. Swap it Out Not every hardware problem is easy to diagnose. If you have a bad motherboard or power supply, their problems may only manifest through occasional odd issues with other components. It’s hard to tell if these components are causing problems unless you replace them completely. Ultimately, the best way to determine whether a component is faulty is to swap it out. For example, if you think your graphics card may be causing your computer to blue screen, pull the graphics card out of your computer and swap in a new graphics card. If everything is working well, it’s likely that your previous graphics card was bad. This isn’t easy for people who don’t have boxes of components sitting around, but it’s the ideal way to troubleshoot. Troubleshooting is all about trial and error, and swapping components out allows you to pin down which component is actually causing the problem through a process of elimination. This isn’t a complete guide to everything that could likely go wrong and how to identify it — someone could write a full textbook on identifying failing components and still not cover everything. But the tips above should give you some places to start dealing with the more common problems. Image Credit: Justin Marty on Flickr     

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  • OS8- AK8- The bad news...

    - by Steve Tunstall
    Ok I told you I would give you the bad news of AK8 to go along with all the cool new stuff, so here it is. It's not that bad, really, just things you need to be aware of. First, the 2013.1 code is being called OS8, AK8 and 2013.1 by different people. I mean different people INSIDE Oracle!! It was supposed to be easy, but it never is. So for the rest of this blog entry, I'm calling it AK8. AK8 is not compatible with the 7x10 series. Ever. The 7x10 series is not supported with AK8, and if you try to upgrade one, it will fail at the healthcheck. All 7x20 series, all of them regardless of age, are supported with AK8. Drive trays. Let's talk about drive trays and SAS cards. The older drive trays for the 7x20 series were called the "Riverwalk 2" or "DS2" trays. They were technically the "J4410" series JBODs that Sun used to sell a la carte before we stopped selling JBODs. Don't get me started on that, it still makes me mad. We used these for many years, and you can still buy them right now until December 15th, 2013, when they will no longer be sold. The DS2 tray only came as a 4u, 24 drive shelf. It held 3.5" drives, and you had a choice of 2TB, 3TB, 300GB or 600GB drives. The SAS HBA in the 7x20 series was called a "Thebe" card, with a part # of 7105394. The 7420, for example, came standard with two of these "Thebe" cards for connecting to the disk trays. Two Thebe cards could handle up to 12 trays, so one would add two more cards to go to 24 trays, or have up to six Thebe cards to handle 36 trays. This card was for external SAS only. It did not connect to the internal OS drives or the Readzillas, both of which used the internal SCSI controller of the server. These Riverwalk 2 trays ARE supported with AK8. You can upgrade your older 7420 or 7320, no problem, as-is. The much older Riverwalk 1 trays or J4400 trays are NOT supported by AK8. However, they were only used by the 7x10 series, and we already said that the 7x10 series was not supported. Here's where it gets tricky. Since last January, we have been selling the new style disk trays. We call them the "DE2-24P" and the "DE2-24C" trays. The "C" tray is for capacity drives, which are 3.5" 3TB or 4TB drives. The "P" trays are for performance drives, which are 2.5" 300GB and 900GB drives. These trays are NOT Riverwalk 2 trays, even though the "C" series may kind of look like it. Different manufacturer and different firmware. They are not new. Like I said, we've been selling them with the 7x20 series since last January. They are the only disk trays we will be selling going forward. Of course, AK8 supports them. So what's the problem? The problem is going to be for people who have to mix drive trays. Remember, your older 7x20 series has Thebe SAS2 HBAs. These have 2 SAS ports per card.  The new ZS3-2 and ZS3-4 systems, however, have the new "Thebe2" SAS2 HBAs. These Thebe2 cards have 4 ports per card. This is very cool, as we can now do more SAS channels with less cards. Instead of needing 4 SAS cards to grow to 24 trays like we did with the old Thebe cards, I can now do 24 trays with only 2 Thebe2 cards. This means more IO slots for fun things like Infiniband and 10G. So far, so good, right? These Thebe2 cards work with any disk tray. You can even mix older DS2 trays with the newer DE2 trays in the same system, as long as you have Thebe2 cards. Ah, there's your problem. You don't have Thebe2 cards in your old 7420, do you? Well, I told you the bad news wasn't that bad, right? We can take out your Thebe cards and replace them with Thebe2. You can then plug your older DS2 trays right back in, and also now get newer DE2 trays going forward. However, it's important that the trays are on different SAS channels. You can mix them in the same system, but not on the same channel. Ask your local SC if you need help with the new cable layout. By the way, the new ZS3-2 and ZS3-4 systems also include a new IO card called "Erie" cards. These are for INTERNAL SAS to the OS drives and the Readzillas. So those are now SAS2 instead of SATA like the older models. Yes, the Erie card uses an IO slot, but that's OK, because the Thebe2 cards allow us to use less SAS HBAs to grow the system, right? That's it. Not too much bad news and really not that bad. AK8 does not support the 7x10 series, and you may need new Thebe2 cards in your older systems if you want to add on newer DE2 trays. I think we can all agree that there are worse things out there. Like our Congress.   Next up.... More good news and cool AK8 tricks. Such as virtual NICS. 

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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