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  • Make dhcp assign same IP and hostname for different interfaces at one machine

    - by Egeshi
    I have a feeling that question itself looks stupid but it is not. Please let me clarify. I have dynamic DNS with BIND and NIS configured at my LAN and have laptop which I am using in both wireless and wired mode. I mean that sometimes I have to use wired interface to achieve higher throughput but most of time I don't need it and using wireless mode. Everything works great. Issue is that I want both interfaces get same IP from DHCP. Just for convenient firewall setup. If I add both hosts to dhcp in this manner # bt wireless host bt { hardware ethernet 00:1f:1f:62:60:28; fixed-address 172.16.77.110; } # bt wired host bt { hardware ethernet 00:14:22:b7:5a:de; fixed-address 172.16.77.110; } DHCP says logs following message dhcpd: Dynamic and static leases present for 172.16.77.110 dhcpd: Remove host declaration bt-wired or remove 172.16.77.110 dhcpd: from the dynamic address pool for 172.16/16 Host records are added outside of any subnet, but it makes no difference if I put them there, effect is still the same. This is not critical but either is not my whim because even if DHCP seems to work fine for that "bt" host, I cannot make connection TO it from remote machine anymore with this definitely incorrect DHCP config. I'd be thankful if one spares a minute for advice about how to configure DHCPD correctly. UPDATE. I realize that there's a soulution to assign different hostname in DHCP config but would like to use benefits of short host names.

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  • Repairing Damage to VMWare Virtual Disk

    - by Lachlan McDonald
    Evening all, I've got a considerable problem I'm hoping to get some resolution on. I had two VMWare 6.5 virtual machines, one running Ubuntu 9.10 and the other Ubuntu 10.04. I used 9.10 as a testing server, so I could install a LAMP environment to prepare some code. Over the months I took a number of snapshots of this VM just in case something went wrong, and did a full copy of the entire VM a month ago. I created the 10.04 VM when Lucid Lynx launched so I could continue development on a fresh install. To get the files over, I simply added the 9.10 virtual disk into the 10.04 VM, grabbed some of the files I needed, and dismounted it. Unknown to me at the time, the changes to the 9.04 virtual disk meant that I could no longer boot it with the 9.10 VM. I'd always get the "The parent virtual disk has been modified since the child was created." error. I decided this was a good time to backup all the critical files, but now whenever I open the 9.04 disk to get the data it isn't in the same state as it was earlier. My question is; is it possible when I'm mounting the virtual disk that I'm not seeing the most recent snapshot, or in my blundering, have I lost the virtual disk. Cheers

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  • how to cause linux system datetime to run faster than real world datetime?

    - by JamesThomasMoon1979
    Background I want to monitor a running linux system over several days. It's a custom gentoo build and with much custom software on board. This software has ongoing maintenance timers and cron scripts and other clock driven events. I need to verify these scheduled events are working. Problem Waiting for the system to step through daily and weekly activity is a long wait time. And modifying all clock-based timers on the system would be time consuming. Yet, I often want to test a system's end-to-end scheduled activities without waiting a week. Potential Solution Have the linux system under test appear to run through it's daily cycle of activity within just a few hours. My Question for Serverfault Is there a way to cause the system's time to run faster than real world time? My first thought is manipulating the ntp daemon to repeatedly and smoothly increment the clock . Any other ideas? And yes, I know this may have strange side affects. However, the system has no important or time critical interactions with systems outside of itself. And this may be a valuable testing technique.

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  • Using mixed disks and OpenFiler to create RAID storage

    - by Cylindric
    I need to improve my home storage to add some resilience. I currently have four disks, as follows: D0: 500Gb (System, Boot) D1: 1Tb D2: 500Gb D3: 250Gb There's a mix of partitions on there, so it's not JBOD, but data is pretty spread out and not redundant. As this is my primary PC and I don't want to give up the entire OS to storage, my plan is to use OpenFiler in a VM to create a virtual SAN. I will also use Windows Software RAID to mirror the OS. Partitions will be created as follows: D0 P1: 100Mb: System-Reserved Boot D0 P2: 50Gb: Virtual Machine VMDKs for OS D0 P3: 350Gb: Data D1 P1: 100Mb: System-Reserved Boot D1 P2: 50Gb: Virtual Machine VMDKs for OS D1 P3: 800Gb: Data D2 P1: 450Gb: Data D3 P1: 200Gb: Data This will result in: Mirrored boot partition Mirrored Operating system Mirrored Virtual machine O/S disks Four partitions for data In the four data partitions I will create several large VMDK files, which I will "mount" into OpenFiler as block-storage devices, combined into three RAID arrays (due to the differing disk sizes) In effect, I'll end up with the following usable partitions SYSTEM 100Mb the small boot partition created by the Windows 7 installer (RAID-1) HOST 50Gb the Windows 7 partition (RAID-1) GUESTS 50Gb Virtual machine Guest VMDK's (RAID-1) VG1 900Gb Volume group consisting of a RAID-5 and two RAID-1 VG2 300Gb Volume group consisting of a single disk On VG1 I can dynamically assign storage for my media, photographs, documents, whatever, and it will be safe. On VG2 I can dynamically assign storage for my data that is not critical, and easily recoverable, as it is not safe. Are there any particular 'gotchas' when implementing a virtual OpenFiler like this? Is the recovery process for a failing disk going to be very problematic? Thanks.

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  • New virtualization project and old SAN

    - by Chris
    Hi, We'll start shortly a partial virtualization of our infrastructure and consolidate a dozen servers into virtuals instances. We'll also add some client application virtualization into the mix for good measure. Two HP DL 380 with the new xeons 56xx and 96 GB of memory each running xenserver + xenapp will then take charge of most of our IT needs. So far, so good. One element that is missing from the picture is the storage part. We need some sort of shared storage to enable live motion and other HA features. We have an IBM DS 4300 SAN that we can use for that. But since it's in production since 2005, I'm not sure about such a critical role for a 5yr old part. So my question is: What is the reliability of this kind of equipment after 5 yr ? Can it last 10 yr with no or few problems ? Since our budjet is tight, not buying another SAN will be a big plus. This lead me to another question: FC disks cost an arm and a leg from IBM. When I type the replacement # in google (for example IBM 300GB 15K 4GBPS FC HDD 42D0410), I can find it at a fraction of the price at various sites. So am I stupid to buy from IBM or naive to trust 3rd party reseller ?? Thanks, Chris

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  • Dell Inspiron 1564 overheating but fan not switching on, how to diagnose?

    - by Smugrik
    I've got a Dell Inspiron 1564 laptop that is about one and a half years old. Since about a week, the laptop started to overheat, causing it to switch off unexpectedly... The cpu fan is working erratically, it can start to spin for a while, doing its job and cooling down the cpu before it stops, but then the temperature goes up, and the fan doesn't reacts, once the temperature reaches a critical point (over 85 celsius, checked with speedfan...), the laptop switches off... I already cleaned the vents and fan from dust, to no avail, and it was actually quite clean anyway. Drivers and bios are up-to-date, no crapware was ever installed on this machine. I don't know how to diagnose the problem, could it be the temperature sensors that sends wrong information, so the fan doesn't reacts? but then I believe the computer wouldn't detect the overheat and stop... Is there a way I can pin point the problem? Maybe some low-level diagnostic tools to check functionality of sensors and fans??? The warranty is already over so any suggestion would be welcome. Thanks!!

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  • Request bursting from web application Load Tests

    - by MaseBase
    I'm migrating our web and database hosting to a new environment on all new machines. I've recently performed a Load Test using WAPT to generate load from multiple distributed clients. The server has plenty of room to handle the traffic load, but I'm seeing an odd pattern of incoming traffic during the load tests. Here is the gist of our setup: Firewall server running MS Forefront TMG 2010 on Win 2k8 server Request routing done by IIS Application Request Routing on firewall machine Web server is a Hyper-V VM on the Database server (which is the host OS) These machines are hefty with dual-CPU's with six cores (12 total procs) Web server running IIS 7.5 Web applications built in ASP.NET 2.0, with 1 ISAPI filter (Url Rewrite) in front What I'm seeing during the load tests is that the requests all come through in bursts. Even though I have 7 different distributed clients sending traffic loads, the requests come through about 300-500 requests at a time. The performance monitor shows nearly all of the counters moving through this pattern, where a burst of requests comes in the req/sec jumps to 70, the queued requests jumps to 500, the current requests jumps up, the CPU jumps up, everything. Then once it's handled that group of requests, it has a lull for nearly 10 seconds where nearly nothing is happening. 0-5 req/sec, 0 queued requests, minimal CPU usage. Then after 10 seconds of inactivity, another burst comes through, spiking all of the counters once again. What I can't figure out is why the requests are coming through in bursts when I know that the load being generated is not sent that way, especially considering the various load-generating clients sending traffic all in different intervals with random think time's between each request. Is there something in the layers between Hyper-V or perhaps in the hardware which might cause this coalesce of requests together? Here is what i'm looking at, the highlighted metric is Requests/sec, but the others critical counter go with it: Requests Queued (which I'd obviously like to keep as close to 0 as possible). Any ideas on this?

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  • Matlab computations done over Apple Filing Protocol (AFP) depend on POSIX permissions, ignores ACLs

    - by flumignan
    I'm a system administrator and have never used Matlab, so forgive my general ignorance of the program. My users have encountered problems when executing scripted Matlab actions over AFP to a Mac OS X Server 10.6.7 where the access control list (ACL) should allow actions, but the POSIX-style permissions disallow the activity. It seems as if Matlab, run locally on the Mac workstations on datasets on the remote server, ignores the ACLs entirely. This is the only application I've ever seen behave this way. The server's filesystem is HFS+J and all other activity is performing as expected. These users cannot use CIFS because of our integration with external directory systems. In this example, the directory bxdata, the members of the group cibturner should be able to modify the files. Indeed, they can using any other method except via Matlab scripts. When the Matlab script hits these files, the POSIX permissions of 644 disallow modification. It's as if the ACLs are irrelevant. [root@cib 16:00:24 /14181.2_5sM]# ls -leh@ bxdata/ total 128 -rw-r--r--+ 1 kel32 staff 18K Feb 15 09:31 TS-5sMath030708-21073-1.edat 0: group:cibturner inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown 1: group:cibsrlocaladmins inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown 2: group:crcservergroup inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown -rw-r--r--+ 1 kel32 staff 25K Feb 15 09:31 TS-5sMath030708-21073-1.txt 0: group:cibturner inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown 1: group:cibsrlocaladmins inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown 2: group:crcservergroup inherited allow read,write,execute,append,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown Because this server has HIPAA data, security is critical. We are not using networked home directories or SAN technology. The MatLab program is run on the user's hard drive; access is granted via Kerberized AFP.

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  • How to stop/kill a virtual machine that hangs in "Stopping" state?

    - by SvetP
    Hi, I have a virtual machine that constantly hangs in the “Stopping” state. I’ve red several posts suggesting killing the vmwp.exe process of the machine but I’ve never been able to kill this process neither from the Windows Task Manager nor from an administrative command prompt by using prockill /PID xxxx /F where xxxx was the process ID. The only result that I have is that my machine enters in “Stopping-Critical” state. Even worse, from that point (having a virtual machine hung at stopping) I am unable to manage (stop or start) any other virtual machine on the same host. The only “solution” in that case for me is to stop the Virtual Machine Management Service (vmms.exe) and to restart the physical host. Without first stopping the vmms.exe service my physical host also hangs during the restart. Moreover, there is no any error logged in the Event Viewer. I’ve found some other posts complaining about them problem. On all of them the only suggestion was to kill the vmwp.exe process, which obviously doesn’t work for them too. Can somebody help us with this, pls? Thanks

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  • Networking Problem MrxSmb event 50 "Delayed Write Failed" errors occurring all of the sudden

    - by Johnny Musso
    JUST THIS MONTH, we have started getting reports from a number of very stable clients that MrxSmb event id 50 errors keep appearing in their system event logs. Otherwise, they do not appear to have any networking problems except that there is a critical legacy application which seems to either be generating the MrxSmb errors or having errors occur because of them. The legacy application is comprised of 16 bit and 32 bit code and has not been changed or recompiled in many years. It has always been stable on Windows XP systems. The customers that have the problem usually have a small (5 clients or less) peer to peer network with all Windows XP systems. All service packs are loaded on the XP machines. Note: The only thing that seems to correct the problem is disabling opportunistic locking. I don't like this solution because it seems to slow down the network and sometimes causes record locking issues between users (on some networks). Also, this seems to have just started happening - as if a Windows update for XP has caused it? However, I have removed recent updates and it did not correct the issue. Thanks in advance for any help you can provide.

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  • VoIP setup for one external PSTN line

    - by Jcl
    I'm completely new to VoIP and the likes, and I'm trying to find information about what could be the best setup for this. I need 4 (maybe more in the future, but maximum 5 or 6) wireless extensions, connected to 1 PSTN line, and maybe 2 in the future. I've been trying to gather information about the gear needed but everything I find seems too much over-the-top (and extremely expensive). The main problem is that the physical place we are on doesn't have possibilities of having a decent internet connection, so using a external VoIP "virtual PBX" is not an option. Thing is, even if small, phone is critical to this organization. I currently have an analog DECT/GAP PBX which does what I need, however the PBX is very bad and the call quality is horrible, and that's why I want to change it. The requirements would be: 4 wireless terminals (routing cable is not an option), all of them ringing on incoming PSTN calls. Ability to do internal calls (4 separate offices) and ability to pass calls between terminals. The 4 terminals should be able to access the external PSTN line without dialing any special codes. Very important: terminals should be able to issue commands on the PSTN line to the external operator in the form *nn*nnnnnnnn# . Don't know wether this could face to be a problem, but I've had problems with analog PBX which would take any * as a PBX command and wouldn't allow terminals to send it to the external lines. Not so important, but would be nice to have: call waiting music Could anyone recommend such a setup? I need to be able to do this on a EXTREMELY LIMITED budget (that is: I don't have a limit, but all should get as much to zero as possible). I have enough spare powerful computers and a 300mbps wireless network which works just fine, so that's not to include in the budget. Don't really know if this is the best place to ask, but it's the most StackExchange-related site I've found to this subject.

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  • Backup with Mercurial and Robocopy?

    - by Andrew Neely
    The Problem We would like to backup our critical files from several network shares to a removable hard drive. We want to automate the backup so we don't have to remember to run it. It needs to finish overnight. Furthermore, we want to be able to preserve multiple versions of each file so we can back out of our user's mistakes easier. Background Information I work in a large Windows-based enterprise with a centralized IT section who is responsible for all backups. Their backups are geared towards disaster recovery and not user error, and require upper-level management approval for any non-disaster recoveries. Several times we have noticed that our backups have failed, we weren't notified. I do not have administrative rights to the server or my desktop. We are trying to backup some 198,000 files spanning about 240 gigabytes. These files rarely change. Our backup drive is one terabyte. My Proposed Solution What I would like to do is to write a batch file using Robocopy with the /mir option along with Mercurial SCM to store all versions of the file. I would do an hg add followed by an hg commit before each execution of Robocopy to save the current state, and then make a mirrored copy of the file structures. The problem is the /mir will delete every folder not present in the source, and Mercurial stores the repository in a .hg folder in the destination folder. Does anybody know how I could either convince Mercurial to store the .hg folder elsewhere, or convince Robocopy not to delete it from the destination? I'm trying to avoid writing a custom program do to copying.

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  • Accidentally mounted a ReiserFS drive as MBR on my windows box - how do I recover?

    - by Ryan
    I had a WD Netcenter with a 160GB drive that kept dropping off the network. I opened up the enclosure and removed the hard drive, connected to a Windows box without knowing the drive used ReiserFS.... When mounting on the Windows box, I chose "MBR" as filesystem. 70GB of data corrupted: 90% of data is word documents, excel spreadsheets, and jpg's - all mission critical. Attempted recovery on Linux box (ubuntu) using TestDisk: I could see the container, but couldn't get anything out – according to TestDisk this was because I chose "none" as filesystem. Attempted recovery using Nucleus Kernel Recovery for windows: 98% of what was recovered is incomplete and/or unusable. I need to know if a way exists to recover or rebuild original ReiserFS MBR, or what tools/techniques might give me the best results in recovering the data. Found a Windows version of TestDisk and I ran it yesterday - here are the results: TestDisk 6.14-WIP, Data Recovery Utility, May 2012 Christophe GRENIER <[email protected]> http://www.cgsecurity.org Disk /dev/sda - 160 GB / 149 GiB - CHS 19457 255 63 The harddisk (160 GB / 149 GiB) seems too small! (< 519 GB / 483 GiB) Check the harddisk size: HD jumpers settings, BIOS detection... The following partitions can't be recovered: Partition Start End Size in sectors > ReiserFS 3.6 62 241 8 19458 0 18 311581568 ReiserFS 3.6 62 248 55 19458 8 2 311581568 ReiserFS 3.6 62 254 37 19458 13 47 311581568 ReiserFS 3.6 63 6 28 19458 20 38 311581568 ReiserFS 3.6 63 13 11 19458 27 21 311581568 ReiserFS 3.6 63 21 43 19458 35 53 311581568 ReiserFS 3.6 63 27 41 19458 41 51 311581568 ReiserFS 3.6 63 37 35 19458 51 45 311581568 ReiserFS 3.6 63 54 20 19458 68 30 311581568 ReiserFS 3.6 63 76 26 19458 90 36 311581568

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  • Windows 7 boot failure after update

    - by Jake
    Installed some windows 7 updates today, mostly just optional fixes and it installed an update to my IntelliType or IntelliPoint drivers (Keyboard & Mouse). It asked to reboot, computer gets to the windows load screen and redirects to the repair utility. Repair utility failed, it said if I recently installed a device, unplug it and try to restart. So I unplugged my keyboard and mouse, restarted. Nothing. I noticed that all the errors seemed to be Windows 7 thinking the installation was on another one of my slave drives. For example, my windows installation is on C:, but I have other drives, like G:, X:, etc... So it said "Critical Boot File G:\Windows\system32\drivers\amdxata.sys is corrupt, but why not C:\ ? So I unplugged ALL other hard drives, it still tried loading X:, even though the only one plugged in was C: I have the windows disk, but that didn't seem to help. I was thinking I need to fix my boot.ini or something simple like that was corrupt, the hard drives seem fine. I'm screwed, it's finals week.

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  • Missing Data on VMWare Virtual Disk

    - by Lachlan McDonald
    Evening all, I've got a considerable problem I'm hoping to get some resolution on. I had two VMWare 6.5 virtual machines, one running Ubuntu 9.10 and the other Ubuntu 10.04. I used 9.10 as a testing server, so I could install a LAMP environment to prepare some code. Over the months I took a number of snapshots of this VM just in case something went wrong, and did a full copy of the entire VM a month ago. I created the 10.04 VM when Lucid Lynx launched so I could continue development on a fresh install. To get the files over, I simply added the 9.10 virtual disk into the 10.04 VM, grabbed some of the files I needed, and dismounted it. Unknown to me at the time, the changes to the 9.04 virtual disk meant that I could no longer boot it with the 9.10 VM. I'd always get the "The parent virtual disk has been modified since the child was created." error. I decided this was a good time to backup all the critical files, but now whenever I open the 9.04 disk to get the data it isn't in the same state as it was earlier. My question is; is it possible when I'm mounting the virtual disk that I'm not seeing the most recent snapshot, or in my blundering, have I lost the virtual disk. Cheers

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  • C# async and actors

    - by Alex.Davies
    If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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  • RAID Volume is no longer showing in Raid Controller BIOS and in Windows

    - by Gordon
    Hi all, I have installed some critical Windows Updates yesterday and now my external RAID Volume no longer shows in Windows Vista x64. All updates went through successfully. For their description, I cannot see how they should relate to the issue, but this is the only change that happened, so who knows. Anyway, here is the details: I have an external eSata enclosure that is running on a SiI4726 controller. I can connect to the controller with it's management utility from the computer the enclosure is connected to. The three drives in the enclosure show up as JBODs. I had those drives configured to be one logical RAID5 drive. RAID management is done through a SiI3132 SoftRaid controller. The Raid Management Utility just shows empty channels where it usually shows the Raid Group. In the Windows Disk Manager, I can see an unknown unitialized device. This is fine according to the setup manual. What it doesn't show is my Raid drive. It's gone. Also, when booting Windows, the BIOS of the controller used to show the RAID volume before booting the OS. This is not happening anymore. Updating drivers and firmware did not help. I have made sure the drivers and firmware are compatible to each others. And like I said, it used to work before. Any clues?

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  • Imaging: Paper Paper Everywhere, but None Should be in Sight

    - by Kellsey Ruppel
    Author: Vikrant Korde, Technical Architect, Aurionpro's Oracle Implementation Services team My wedding photos are stored in several empty shoeboxes. Yes...I got married before digital photography was mainstream...which means I'm old. But my parents are really old. They have shoeboxes filled with vacation photos on slides (I doubt many of you have even seen a home slide projector...and I hope you never do!). Neither me nor my parents should have shoeboxes filled with any form of photographs whatsoever. They should obviously live in the digital world...with no physical versions in sight (other than a few framed on our walls). Businesses grapple with similar challenges. But instead of shoeboxes, they have file cabinets and warehouses jam packed with paper invoices, legal documents, human resource files, material safety data sheets, incident reports, and the list goes on and on. In fact, regulatory and compliance rules govern many industries, requiring that this paperwork is available for any number of years. It's a real challenge...especially trying to find archived documents quickly and many times with no backup. Which brings us to a set of technologies called Image Process Management (or simply Imaging or Image Processing) that are transforming these antiquated, paper-based processes. Oracle's WebCenter Content Imaging solution is a combination of their WebCenter suite, which offers a robust set of content and document management features, and their Business Process Management (BPM) suite, which helps to automate business processes through the definition of workflows and business rules. Overall, the solution provides an enterprise-class platform for end-to-end management of document images within transactional business processes. It's a solution that provides all of the capabilities needed - from document capture and recognition, to imaging and workflow - to effectively transform your ‘shoeboxes’ of files into digitally managed assets that comply with strict industry regulations. The terminology can be quite overwhelming if you're new to the space, so we've provided a summary of the primary components of the solution below, along with a short description of the two paths that can be executed to load images of scanned documents into Oracle's WebCenter suite. WebCenter Imaging (WCI): the electronic document repository that provides security, annotations, and search capabilities, and is the primary user interface for managing work items in the imaging solution SOA & BPM Suites (workflow): provide business process management capabilities, including human tasks, workflow management, service integration, and all other standard SOA features. It's interesting to note that there a number of 'jumpstart' processes available to help accelerate the integration of business applications, such as the accounts payable invoice processing solution for E-Business Suite that facilitates the processing of large volumes of invoices WebCenter Enterprise Capture (WEC): expedites the capture process of paper documents to digital images, offering high volume scanning and importing from email, and allows for flexible indexing options WebCenter Forms Recognition (WFR): automatically recognizes, categorizes, and extracts information from paper documents with greatly reduced human intervention WebCenter Content: the backend content server that provides versioning, security, and content storage There are two paths that can be executed to send data from WebCenter Capture to WebCenter Imaging, both of which are described below: 1. Direct Flow - This is the simplest and quickest way to push an image scanned from WebCenter Enterprise Capture (WEC) to WebCenter Imaging (WCI), using the bare minimum metadata. The WEC activities are defined below: The paper document is scanned (or imported from email). The scanned image is indexed using a predefined indexing profile. The image is committed directly into the process flow 2. WFR (WebCenter Forms Recognition) Flow - This is the more complex process, during which data is extracted from the image using a series of operations including Optical Character Recognition (OCR), Classification, Extraction, and Export. This process creates three files (Tiff, XML, and TXT), which are fed to the WCI Input Agent (the high speed import/filing module). The WCI Input Agent directory is a standard ingestion method for adding content to WebCenter Imaging, the process for doing so is described below: WEC commits the batch using the respective commit profile. A TIFF file is created, passing data through the file name by including values separated by "_" (underscores). WFR completes OCR, classification, extraction, export, and pulls the data from the image. In addition to the TIFF file, which contains the document image, an XML file containing the extracted data, and a TXT file containing the metadata that will be filled in WCI, are also created. All three files are exported to WCI's Input agent directory. Based on previously defined "input masks", the WCI Input Agent will pick up the seeding file (often the TXT file). Finally, the TIFF file is pushed in UCM and a unique web-viewable URL is created. Based on the mapping data read from the TXT file, a new record is created in the WCI application.  Although these processes may seem complex, each Oracle component works seamlessly together to achieve a high performing and scalable platform. The solution has been field tested at some of the largest enterprises in the world and has transformed millions and millions of paper-based documents to more easily manageable digital assets. For more information on how an Imaging solution can help your business, please contact [email protected] (for U.S. West inquiries) or [email protected] (for U.S. East inquiries). About the Author: Vikrant is a Technical Architect in Aurionpro's Oracle Implementation Services team, where he delivers WebCenter-based Content and Imaging solutions to Fortune 1000 clients. With more than twelve years of experience designing, developing, and implementing Java-based software solutions, Vikrant was one of the founding members of Aurionpro's WebCenter-based offshore delivery team. He can be reached at [email protected].

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  • How to backup a NAS drive to a USB drive?

    - by Tim Murphy
    How would you backup 600+ GB of data on a NAS (Network-Attached Storage) drive to a USB external drive? The NAS drive does not contain mission critical data nonetheless I wish to make weekly copies of it just in case. The NAS drive is almost exclusively used as an archive dump and is rarely updated. However the backup strategy used must have a simple restore procedure so I can confidently say the data now on the NAS drive is exactly how it was at the time of backup. I did try xcopy but seemed like it would take many-many hours and eventually crashed with insufficient memory. http://www.ctunion.com/node/114 suggests I would need to use xxcopy instead due to folder/file name lengths. My concern with xcopy/xxcopy is the length of time it takes. Hoping something else is faster. NAS drive is DLink DNS-313. 1TB drive installed. Connected to router via Ethernet cable. USB drive is Seagate 1TB. Can be connected to Windows Vista (preferred) or Windows 7 PCs. Both PCs are usually connected Wirelessly however ethernet cable can be used during backup to speed up the process.

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  • Some non-generic collections

    - by Simon Cooper
    Although the collections classes introduced in .NET 2, 3.5 and 4 cover most scenarios, there are still some .NET 1 collections that don't have generic counterparts. In this post, I'll be examining what they do, why you might use them, and some things you'll need to bear in mind when doing so. BitArray System.Collections.BitArray is conceptually the same as a List<bool>, but whereas List<bool> stores each boolean in a single byte (as that's what the backing bool[] does), BitArray uses a single bit to store each value, and uses various bitmasks to access each bit individually. This means that BitArray is eight times smaller than a List<bool>. Furthermore, BitArray has some useful functions for bitmasks, like And, Xor and Not, and it's not limited to 32 or 64 bits; a BitArray can hold as many bits as you need. However, it's not all roses and kittens. There are some fundamental limitations you have to bear in mind when using BitArray: It's a non-generic collection. The enumerator returns object (a boxed boolean), rather than an unboxed bool. This means that if you do this: foreach (bool b in bitArray) { ... } Every single boolean value will be boxed, then unboxed. And if you do this: foreach (var b in bitArray) { ... } you'll have to manually unbox b on every iteration, as it'll come out of the enumerator an object. Instead, you should manually iterate over the collection using a for loop: for (int i=0; i<bitArray.Length; i++) { bool b = bitArray[i]; ... } Following on from that, if you want to use BitArray in the context of an IEnumerable<bool>, ICollection<bool> or IList<bool>, you'll need to write a wrapper class, or use the Enumerable.Cast<bool> extension method (although Cast would box and unbox every value you get out of it). There is no Add or Remove method. You specify the number of bits you need in the constructor, and that's what you get. You can change the length yourself using the Length property setter though. It doesn't implement IList. Although not really important if you're writing a generic wrapper around it, it is something to bear in mind if you're using it with pre-generic code. However, if you use BitArray carefully, it can provide significant gains over a List<bool> for functionality and efficiency of space. OrderedDictionary System.Collections.Specialized.OrderedDictionary does exactly what you would expect - it's an IDictionary that maintains items in the order they are added. It does this by storing key/value pairs in a Hashtable (to get O(1) key lookup) and an ArrayList (to maintain the order). You can access values by key or index, and insert or remove items at a particular index. The enumerator returns items in index order. However, the Keys and Values properties return ICollection, not IList, as you might expect; CopyTo doesn't maintain the same ordering, as it copies from the backing Hashtable, not ArrayList; and any operations that insert or remove items from the middle of the collection are O(n), just like a normal list. In short; don't use this class. If you need some sort of ordered dictionary, it would be better to write your own generic dictionary combining a Dictionary<TKey, TValue> and List<KeyValuePair<TKey, TValue>> or List<TKey> for your specific situation. ListDictionary and HybridDictionary To look at why you might want to use ListDictionary or HybridDictionary, we need to examine the performance of these dictionaries compared to Hashtable and Dictionary<object, object>. For this test, I added n items to each collection, then randomly accessed n/2 items: So, what's going on here? Well, ListDictionary is implemented as a linked list of key/value pairs; all operations on the dictionary require an O(n) search through the list. However, for small n, the constant factor that big-o notation doesn't measure is much lower than the hashing overhead of Hashtable or Dictionary. HybridDictionary combines a Hashtable and ListDictionary; for small n, it uses a backing ListDictionary, but switches to a Hashtable when it gets to 9 items (you can see the point it switches from a ListDictionary to Hashtable in the graph). Apart from that, it's got very similar performance to Hashtable. So why would you want to use either of these? In short, you wouldn't. Any gain in performance by using ListDictionary over Dictionary<TKey, TValue> would be offset by the generic dictionary not having to cast or box the items you store, something the graphs above don't measure. Only if the performance of the dictionary is vital, the dictionary will hold less than 30 items, and you don't need type safety, would you use ListDictionary over the generic Dictionary. And even then, there's probably more useful performance gains you can make elsewhere.

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  • Xen domU passwd file overwritten with console log output

    - by malfy
    I was setting up a Debian Xen domU and after booting it fine, I added basic configuration to /etc/network/interfaces and ran /etc/init.d/networking restart. This failed so I decided to reboot. After the reboot I also ran xm shutdown box. When dropped to a shell prompt it wouldn't let me login. Upon further inspection, I now have garbage in some critical files in /etc: root@box:/# tail +1 mnt/etc/{passwd-,shadow} tail: cannot open `+1' for reading: No such file or directory ==> mnt/etc/passwd- <== 0000000000100000 (reserved) Nov 23 02:02:39 box kernel: [ 0.000000] Xen: 0000000000100000 - 0000000004000000 (usable) Nov 23 02:02:39 box kernel: [ 0.000000] DMI not present or invalid. Nov 23 02:02:39 box kernel: [ 0.000000] last_pfn = 0x4000 max_arch_pfn = 0x1000000 Nov 23 02:02:39 box kernel: [ 0.000000] initial memory mapped : 0 - 033ff000 Nov 23 02:02:39 box kernel: [ 0.000000] init_memory_mapping: 0000000000000000-0000000004000000 Nov 23 02:02:39 box kernel: [ 0.000000] NX (Execute Disable) protection: active Nov 23 02:02:39 box kernel: [ 0.000000] 0000000000 - 0004000000 page 4k Nov 23 02:02:39 box kernel: [ 0.000000] kernel direct mapping tables up to 4000000 @ 7000-2c000 Nov 23 02:02:3 ==> mnt/etc/shadow <== 32 nr_cpumask_bits:32 nr_cpu_ids:1 nr_node_ids:1 Nov 23 02:02:39 box kernel: [ 0.000000] PERCPU: Embedded 15 pages/cpu @c15b0000 s37688 r0 d23752 u65536 Nov 23 02:02:39 box kernel: [ 0.000000] pcpu-alloc: s37688 r0 d23752 u65536 alloc=16*4096 Nov 23 02:02:39 box kernel: [ 0.000000] pcpu-alloc: [0] 0 Nov 23 02:02:39 box kernel: [ 0.000000] Xen: using vcpu_info placement Nov 23 02:02:39 box kernel: [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16160 Nov 23 02:02:39 box kernel: [ 0.000000] Kernel command line: root=/dev/mapper/xen-guest_root ro quiet root=/dev/xvda1 ro Nov 23 02:02:39 box kernel: [ 0.000000] PID hash table entries: The garbage is also present in the passwd file and the group file (although I didn't paste that above since I have since ran debootstrap on the filesystem again). Does anyone have any insight into what happened and why?

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  • InnoDB Compression Improvements in MySQL 5.6

    - by Inaam Rana
    MySQL 5.6 comes with significant improvements for the compression support inside InnoDB. The enhancements that we'll talk about in this piece are also a good example of community contributions. The work on these was conceived, implemented and contributed by the engineers at Facebook. Before we plunge into the details let us familiarize ourselves with some of the key concepts surrounding InnoDB compression. In InnoDB compressed pages are fixed size. Supported sizes are 1, 2, 4, 8 and 16K. The compressed page size is specified at table creation time. InnoDB uses zlib for compression. InnoDB buffer pool will attempt to cache compressed pages like normal pages. However, whenever a page is actively used by a transaction, we'll always have the uncompressed version of the page as well i.e.: we can have a page in the buffer pool in compressed only form or in a state where we have both the compressed page and uncompressed version but we'll never have a page in uncompressed only form. On-disk we'll always only have the compressed page. When both compressed and uncompressed images are present in the buffer pool they are always kept in sync i.e.: changes are applied to both atomically. Recompression happens when changes are made to the compressed data. In order to minimize recompressions InnoDB maintains a modification log within a compressed page. This is the extra space available in the page after compression and it is used to log modifications to the compressed data thus avoiding recompressions. DELETE (and ROLLBACK of DELETE) and purge can be performed without recompressing the page. This is because the delete-mark bit and the system fields DB_TRX_ID and DB_ROLL_PTR are stored in uncompressed format on the compressed page. A record can be purged by shuffling entries in the compressed page directory. This can also be useful for updates of indexed columns, because UPDATE of a key is mapped to INSERT+DELETE+purge. A compression failure happens when we attempt to recompress a page and it does not fit in the fixed size. In such case, we first try to reorganize the page and attempt to recompress and if that fails as well then we split the page into two and recompress both pages. Now lets talk about the three major improvements that we made in MySQL 5.6.Logging of Compressed Page Images:InnoDB used to log entire compressed data on the page to the redo logs when recompression happens. This was an extra safety measure to guard against the rare case where an attempt is made to do recovery using a different zlib version from the one that was used before the crash. Because recovery is a page level operation in InnoDB we have to be sure that all recompress attempts must succeed without causing a btree page split. However, writing entire compressed data images to the redo log files not only makes the operation heavy duty but can also adversely affect flushing activity. This happens because redo space is used in a circular fashion and when we generate much more than normal redo we fill up the space much more quickly and in order to reuse the redo space we have to flush the corresponding dirty pages from the buffer pool.Starting with MySQL 5.6 a new global configuration parameter innodb_log_compressed_pages. The default value is true which is same as the current behavior. If you are sure that you are not going to attempt to recover from a crash using a different version of zlib then you should set this parameter to false. This is a dynamic parameter.Compression Level:You can now set the compression level that zlib should choose to compress the data. The global parameter is innodb_compression_level - the default value is 6 (the zlib default) and allowed values are 1 to 9. Again the parameter is dynamic i.e.: you can change it on the fly.Dynamic Padding to Reduce Compression Failures:Compression failures are expensive in terms of CPU. We go through the hoops of recompress, failure, reorganize, recompress, failure and finally page split. At the same time, how often we encounter compression failure depends largely on the compressibility of the data. In MySQL 5.6, courtesy of Facebook engineers, we have an adaptive algorithm based on per-index statistics that we gather about compression operations. The idea is that if a certain index/table is experiencing too many compression failures then we should try to pack the 16K uncompressed version of the page less densely i.e.: we let some space in the 16K page go unused in an attempt that the recompression won't end up in a failure. In other words, we dynamically keep adding 'pad' to the 16K page till we get compression failures within an agreeable range. It works the other way as well, that is we'll keep removing the pad if failure rate is fairly low. To tune the padding effort two configuration variables are exposed. innodb_compression_failure_threshold_pct: default 5, range 0 - 100,dynamic, implies the percentage of compress ops to fail before we start using to padding. Value 0 has a special meaning of disabling the padding. innodb_compression_pad_pct_max: default 50, range 0 - 75, dynamic, the  maximum percentage of uncompressed data page that can be reserved as pad.

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  • What is the quickest reliable way to backup a NAS drive to a USB drive?

    - by Tim Murphy
    How would you backup 600+ GB of data on a NAS (Network-Attached Storage) drive to a USB external drive? The NAS drive does not contain mission critical data nonetheless I wish to make weekly copies of it just in case. The NAS drive is almost exclusively used as an archive dump and is rarely updated. However the backup strategy used must have a simple restore procedure so I can confidently say the data now on the NAS drive is exactly how it was at the time of backup. I did try xcopy but seemed like it would take many-many hours and eventually crashed with insufficient memory. http://www.ctunion.com/node/114 suggests I would need to use xxcopy instead due to folder/file name lengths. My concern with xcopy/xxcopy is the length of time it takes. Hoping something else is faster. NAS drive is DLink DNS-313. 1TB drive installed. Connected to router via Ethernet cable. USB drive is Seagate 1TB. Can be connected to Windows Vista (preferred) or Windows 7 PCs. Both PCs are usually connected Wirelessly however ethernet cable can be used during backup to speed up the process.

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  • Performance associated with storing millions of files on NTFS

    - by Tim Brigham
    Does anyone have a method / formula, etc that I could use - hopefully based on both current and projected numbers of files - to project the 'right' length of the split and the number of nested folders? Please note that although similar it isn't quite the same as Storing a million images in the filesystem. I'm looking for a way to help make the theories outlined more generic. Assumptions I have 'some' initial number of files. This number would be arbitrary but large. Say 500k to 10m+. I have considered the underlying physical hardware disk IO requirements that would be necessary to support such an endeavor. Put another way As time progresses this store will grow. I want to have the best balance of current performance and as my needs increase. Say I double or triple my storage. I need to be able to address both current needs and projected future growth. I need to both plan ahead and not sacrifice too much of current performance. What I've come up with I'm already thinking about using a hash split every so many characters to split things out across multiple directories and keeping the trees even, very similar as outlined in the comments in the question above. It also avoids duplicate files, which would be critical over time. I'm sure that the initial folder structure would be different based on what I've outlined, and depending on the initial scale. As far as I can figure there isn't a one size fits all solution here. It would be horrendously time intensive to work something out experimentally.

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  • How can I recover a Fedora 12 installation that is showing signs of disk errors?

    - by Bob Cross
    I am currently overseas (i.e., very far from my normal library of tools) and my primary machine that would normally act as the data server in the performance test that we're trying to run is failing to boot to Fedora 12 properly. This is a machine that, as of yesterday, was booting fine. However, this morning, very strange portions of the boot process were complaining with messages such as "unexpected 0x0 in rpcbind" and "bad file descriptor" (I don't have the error in front of me - scavenged a windows installation to get onto serverfault). Eventually, the boot hung for a long time at the NFS service and then brought up what looked like the KDE login screen but neither the mouse nor keyboard functioned. In olden days, I would try to get to a point where I could manage to run fsck and pray that the bad sectors would come back into alignment just long enough for me to scrape the critical data off of the machine. However, now that we live in the future, it seems like our options in situations like this should be a little more varied. Is there a way to recover a Fedora 12 installation with bad disk sectors that won't boot properly? For completeness, I am comfortable working with bootable recovery distros-on-CD and such but I don't know which one is likely to work best with modern Fedora. In the absence of guidance, I'm frantically torrenting the Fedora 12 Live CD and DVD, hoping to try rescue mode before tomorrow morning.

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