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  • Suspended Laptop Cannot Wake Up - Ubuntu

    - by Zack
    I've got an ASUS G73JH, and whenever I suspend it or hibernate it, it will not wake up. The screen stays backlight but is black. The fan remains running, however the HDD does not, not disk activity is noticeable (audibly (It's not a SSD)). I can't: Awaken it with the keyboard Awaken it with the mouse Soft power-off by pressing the power button Change virtual screens by pressing Ctrl-Alt-# Restart X by pressing Ctrl-Alt-Backspace I have to hold down the power button and shut it down that way, and this seems a little unreasonable. Is there a place I could look for more detail as to what's causing this? Is there a known quick-fix to this issue? Nothing is logged as happening when the system is in "suspend" mode. Here's what happened immediately before and after the suspend "happened," note the time gap: May 4 17:46:13 tofu NetworkManager: <info> (eth0): carrier now OFF (device state 1) May 4 17:48:57 tofu kernel: imklog 4.2.0, log source = /proc/kmsg started. This one's kinda long, here's what happened immediately before the suspend, I'm not sure if it'll help but if you can find a use for it: May 4 17:46:10 tofu anacron[3353]: Anacron 2.3 started on 2010-05-04 May 4 17:46:10 tofu anacron[3353]: Normal exit (0 jobs run) May 4 17:46:10 tofu kernel: [ 2241.775927] CPU0 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.775958] CPU1 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.775987] CPU2 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.776138] CPU3 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.776168] CPU4 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.776197] CPU5 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.776200] CPU6 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.776229] CPU7 attaching NULL sched-domain. May 4 17:46:10 tofu kernel: [ 2241.919611] CPU0 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.919668] domain 0: span 0,4 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.919699] groups: 0 (cpu_power = 589) 4 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.919733] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.919762] groups: 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.919850] CPU1 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.919852] domain 0: span 1,5 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.919881] groups: 1 (cpu_power = 589) 5 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.919912] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.919915] groups: 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920003] CPU2 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920005] domain 0: span 2,6 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920033] groups: 2 (cpu_power = 589) 6 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920065] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920093] groups: 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920155] CPU3 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920157] domain 0: span 3,7 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920185] groups: 3 (cpu_power = 589) 7 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920217] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920245] groups: 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920307] CPU4 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920335] domain 0: span 0,4 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920337] groups: 4 (cpu_power = 589) 0 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920368] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920397] groups: 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920459] CPU5 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920487] domain 0: span 1,5 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920489] groups: 5 (cpu_power = 589) 1 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920520] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920549] groups: 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920611] CPU6 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920639] domain 0: span 2,6 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920641] groups: 6 (cpu_power = 589) 2 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920699] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920701] groups: 2,6 (cpu_power = 1178) 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) May 4 17:46:10 tofu kernel: [ 2241.920762] CPU7 attaching sched-domain: May 4 17:46:10 tofu kernel: [ 2241.920791] domain 0: span 3,7 level SIBLING May 4 17:46:10 tofu kernel: [ 2241.920793] groups: 7 (cpu_power = 589) 3 (cpu_power = 589) May 4 17:46:10 tofu kernel: [ 2241.920851] domain 1: span 0-7 level MC May 4 17:46:10 tofu kernel: [ 2241.920853] groups: 3,7 (cpu_power = 1178) 0,4 (cpu_power = 1178) 1,5 (cpu_power = 1178) 2,6 (cpu_power = 1178) May 4 17:46:12 tofu NetworkManager: <info> Sleeping... May 4 17:46:12 tofu NetworkManager: <info> (wlan0): now unmanaged May 4 17:46:12 tofu NetworkManager: <info> (wlan0): device state change: 8 -> 1 (reason 37) May 4 17:46:12 tofu NetworkManager: <info> (wlan0): deactivating device (reason: 37). May 4 17:46:12 tofu NetworkManager: <info> (wlan0): canceled DHCP transaction, dhcp client pid 1984 May 4 17:46:12 tofu kernel: [ 2244.084515] wlan0: deauthenticating from 68:7f:74:23:02:ae by local choice (reason=3) May 4 17:46:12 tofu avahi-daemon[1176]: Withdrawing address record for 192.168.1.2 on wlan0. May 4 17:46:12 tofu avahi-daemon[1176]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.1.2. May 4 17:46:12 tofu avahi-daemon[1176]: Interface wlan0.IPv4 no longer relevant for mDNS. May 4 17:46:12 tofu NetworkManager: <info> Policy set 'Auto eth0' (eth0) as default for routing and DNS. May 4 17:46:12 tofu NetworkManager: <info> (wlan0): cleaning up... May 4 17:46:12 tofu NetworkManager: <info> (wlan0): taking down device. May 4 17:46:12 tofu avahi-daemon[1176]: Withdrawing address record for 2002:4c6e:638a:0:1e4b:d6ff:fe78:951d on wlan0. May 4 17:46:12 tofu wpa_supplicant[1212]: CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys May 4 17:46:13 tofu NetworkManager: <info> (eth0): now unmanaged May 4 17:46:13 tofu NetworkManager: <info> (eth0): device state change: 8 -> 1 (reason 37) May 4 17:46:13 tofu NetworkManager: <info> (eth0): deactivating device (reason: 37). May 4 17:46:13 tofu NetworkManager: <info> (eth0): canceled DHCP transaction, dhcp client pid 1559 May 4 17:46:13 tofu NetworkManager: <WARN> check_one_route(): (eth0) error -34 returned from rtnl_route_del(): Sucess#012 May 4 17:46:13 tofu avahi-daemon[1176]: Withdrawing address record for 192.168.1.3 on eth0. May 4 17:46:13 tofu avahi-daemon[1176]: Leaving mDNS multicast group on interface eth0.IPv4 with address 192.168.1.3. May 4 17:46:13 tofu avahi-daemon[1176]: Interface eth0.IPv4 no longer relevant for mDNS. May 4 17:46:13 tofu NetworkManager: <info> (eth0): cleaning up... May 4 17:46:13 tofu NetworkManager: <info> (eth0): taking down device. May 4 17:46:13 tofu avahi-daemon[1176]: Withdrawing address record for 2002:4c6e:638a:0:4a5b:39ff:fe0b:325d on eth0. May 4 17:46:13 tofu NetworkManager: <info> (eth0): carrier now OFF (device state 1)

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  • Getting really weird long Contact Group names

    - by Pentium10
    When looking at the Contact Groups on Google Contacts or in the People application of my HTC Legend phone, I get the groups names ok eg: Friends, Family, VIP, Favorite etc... But in my application I get really wrong names such as "Family" became "System Group: Family" "Friends" became "System Group: Friends" "Favorite" became "Favorite_5656100000000_3245664334564" I use the below code to read these values: public Cursor getFromSystem() { // Get the base URI for the People table in the Contacts content // provider. Uri contacts = ContactsContract.Groups.CONTENT_URI; // Make the query. ContentResolver cr = ctx.getContentResolver(); // Form an array specifying which columns to return. String[] projection = new String[] { ContactsContract.Groups._ID, ContactsContract.Groups.TITLE, ContactsContract.Groups.NOTES }; Cursor managedCursor = cr.query(contacts, projection, ContactsContract.Groups.DELETED + "=0", null, ContactsContract.Groups.TITLE + " COLLATE LOCALIZED ASC"); return managedCursor; } What I am missing?

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  • Examples using Active Directory/LDAP groups for permissions \ roles in Rails App.

    - by Nick Gorbikoff
    Hello. I was wondering how other people implemented this scenario. I have an internal rails app ( inventory management, label printing, shipping,etc). I'm rewriting security on the system, cause the old way got to cumbersome to maintain ( users table, passwords, roles) - I used restful_authentication and roles. It was implemented about 3 years ago. I already implemented AuthLogic with ruby-ldap-net to authenticate users ( actually that was surprisingly easy, compared to how I struggled with other frameworks/languages before). Next step is roles. I already have groups defined in Active Directory - so I don't want to run a separate roles system in my rails app, I just want to reuse Active Directory groups - since that part of the system is already maintained for other purposes ( shared drives, backups, pc access, etc) So I was wondering if others had experience implementing permissions/roles in a rails app based on groups in Active Directory or LDAP. Also the roles requirements are pretty complex. Here is an example: For instance I have users that belong to the supervisors group in AD and to inventory dept, so I was that user to be able to run "advanced" tasks in invetory - adjust qty, run reports, however other "supervisors" from other departmanets, shouldn't be able to do this, also Top Management - should be able to use those reports (regardless weather they belong to the invetory or not), but not Middle Management, unless they are in inventory group. Admins of the system (Domain Admins) should have unrestricted access to the system , except for HR & Finances part unless they are in HR ( like you don't want all system admins (except for one authorized one) to see personal info of other employees). I looked at acl9, cancan, aegis. I was wondering if there are any advantaged/cons to using one versus the other for this particular use of system access based on AD. Suggest other systems if you had good experience. Thank you!!!

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  • How use DNS server to create simple HA (High availability) of my website?

    - by marc22
    Welcome, How can i use DNS server to create simple HA (High availability) of website ? For example if my web-server ( for better understanding i use internal IP in real it will be other hosting companies) 192.168.0.120 :80 (is offline) traffic go to 192.168.0.130 :80 You have right, i use bad word "hight avability" of course i was thinking about failover. Using few IP in A records is good for simple load-balancing. But not in case, if i want notice user about failure (for example display page, Oops something is wrong without our server, we working on it) against "can't establish connection". I was thinking about setting up something like this 2 DNS servers, one installed on www server Both have low TTL on my domain, set up 2 ns records first for DNS with my apache server second to other dns If user try connect he will get ip of www server using first dns, if that dns is offline (probably www server is also down) so it will try second NS record, what will point to another dns, that dns will point to "backup" page. That's what i would like to do. If You have other idea please share. Reverse proxy is not option, because IP of server can change, or i can use other country for backup.

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  • Having a list of rooms with theirs connection to each other, how do I find isolated room groups?

    - by petervaz
    I'm trying to create a small roguelike and went as far as random generating rooms and corridors. Each room is an instanced object and contain an arraylist of the others rooms connected by a corridor. I can single out unconnected rooms but how can I know the rooms that are connected only to each other but not to most of the others, forming an island? to illustrated better the problem here is an image from the console on a bogged level. Rooms 5 and 6 are connected only to each other. What algorithm can I use to detect that?

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  • Is there any utility in windows 7 that is similar to Local Users and Groups snap-in ?

    - by Janis Veinbergs
    Hello. Windows 7 Home Premium has local users and groups mmc console snap-in disabled: Is there any custom utility I can use to manage my accounts? I need no more than adding users and email addresses to have some test accounts for my development purposes. I don't want to use regular "user accounts" tool in control panel to add users because: I don't want them at my welcome screen I can't assign mail address to them

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  • In AD how to get groups the workstation is a member of from the workstation itself?

    - by David
    If I'm at the domain controller (in the Active Directory) to find out what groups the "XPSP3-A" workstation is a member of, I do: dsquery computer "CN=XPSP3-A,CN=Computers,DC=pvk,DC=local" -name XPSP3-A | dsget computer -memberof and receive the following: "CN=Sec Group 001,OU=OU1,DC=pvk,DC=local" "CN=Domain Computers,CN=Users,DC=pvk,DC=local" But how to do the same from the "XPSP3-A" workstation?

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  • How to use Nexus groups with Hudson to deploy artifacts post-build?

    - by John
    Hi there. I'm currently setting up Hudson to push artifacts to my Nexus repository upon succesful builds. Unfortunately I am having some trouble with getting Hudson to deploy using Nexus groups. I have two groups, upbeat.nexus (private) and public.nexus (public). I've set up the associated repositories in Nexus already. Here's my settings.xml: <settings> <mirrors> <mirror> <id>upbeat.nexus</id> <mirrorOf>*</mirrorOf> <url>http://localhost:8099/nexus/content/groups/upbeat</url> </mirror> <mirror> <id>public.nexus</id> <mirrorOf>*</mirrorOf> <url>http://localhost:8099/nexus/content/groups/public</url> </mirror> </mirrors> <profiles> <profile> <id>upbeat.nexus</id> <repositories> <repository> <id>upbeat.central</id> <url>http://central</url> <releases><enabled>true</enabled></releases> <snapshots><enabled>true</enabled></snapshots> </repository> </repositories> </profile> <profile> <id>public.nexus</id> <repositories> <repository> <id>public.central</id> <url>http://central</url> <releases><enabled>true</enabled></releases> <snapshots><enabled>true</enabled></snapshots> </repository> </repositories> </profile> </profiles> <servers> <server> <id>upbeat.nexus</id> <username>build</username> <password></password> </server> <server> <id>public.nexus</id> <username>build</username> <password></password> </server> </servers> <activeProfiles> <activeProfile>upbeat.nexus</activeProfile> <activeProfile>public.nexus</activeProfile> </activeProfiles> In Hudson, when setting the "Deploy artifacts to Maven repository", I need to specify the repository URL and the repository ID. I've set the repository ID to "public.nexus" but if I set the URL to http://forge.upbeat.no/nexus/content/repositories/public and the ID to public.nexus I get the following error: Deploying artifacts to http://forge.upbeat.no/nexus/content/repositories/public Deploying the main artifact pom.xml [INFO ] Retrieving previous build number from public.nexus [INFO ] repository metadata for: 'snapshot com.upbeat.appl:skuldweb:1.0-SNAPSHOT' could not be found on repository: public.nexus, so will be created ERROR: Error deploying artifact: Failed to transfer file: http://forge.upbeat.no/nexus/content/repositories/public/com/upbeat/appl/skuldweb/1.0-SNAPSHOT/skuldweb-1.0-SNAPSHOT.pom. Return code is: 400 org.apache.maven.artifact.deployer.ArtifactDeploymentException: Error deploying artifact: Failed to transfer file: http://forge.upbeat.no/nexus/content/repositories/public/com/upbeat/appl/skuldweb/1.0-SNAPSHOT/skuldweb-1.0-SNAPSHOT.pom. Return code is: 400 at org.apache.maven.artifact.deployer.DefaultArtifactDeployer.deploy(DefaultArtifactDeployer.java:94) at hudson.maven.reporters.MavenArtifactRecord.deploy(MavenArtifactRecord.java:119) at hudson.maven.reporters.MavenAggregatedArtifactRecord.deploy(MavenAggregatedArtifactRecord.java:79) at hudson.maven.RedeployPublisher.perform(RedeployPublisher.java:109) at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19) at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:601) at hudson.model.AbstractBuild$AbstractRunner.performAllBuildSteps(AbstractBuild.java:580) at hudson.maven.MavenModuleSetBuild$RunnerImpl.post2(MavenModuleSetBuild.java:598) at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:528) at hudson.model.Run.run(Run.java:1264) at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:306) at hudson.model.ResourceController.execute(ResourceController.java:88) at hudson.model.Executor.run(Executor.java:124) Caused by: org.apache.maven.wagon.TransferFailedException: Failed to transfer file: http://forge.upbeat.no/nexus/content/repositories/public/com/upbeat/appl/skuldweb/1.0-SNAPSHOT/skuldweb-1.0-SNAPSHOT.pom. Return code is: 400 at org.apache.maven.wagon.providers.http.LightweightHttpWagon.put(LightweightHttpWagon.java:172) at org.apache.maven.artifact.manager.DefaultWagonManager.putRemoteFile(DefaultWagonManager.java:244) at org.apache.maven.artifact.manager.DefaultWagonManager.putArtifact(DefaultWagonManager.java:160) at org.apache.maven.artifact.deployer.DefaultArtifactDeployer.deploy(DefaultArtifactDeployer.java:80) ... 12 more Finished: FAILURE Any tips on how to deploy to a group so I don't have to specify (in Hudson) whether or not I am building a snapshot or a release version, and instead have it look at the version-tag in the pom to automatically place the artifact in the correct repository?

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  • Efficient algorithm for creating an ideal distribution of groups into containers?

    - by Inshim
    I have groups of students that need to be allocated into classrooms of a fixed capacity (say, 100 chairs in each). Each group must only be allocated to a single classroom, even if it is larger than the capacity (ie there can be an overflow, with students standing up) I need an algorithm to make the allocations with minimum overflows and under-capacity classrooms. A naive algorithm to do this allocation is horrendously slow when having ~200 groups, with a distribution of about half of them being under 20% of the classroom size. Any ideas where I can find at least some good starting point for making this algorithm lightning fast? Thanks!

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  • Is there anJoomla extensions that works like Yahoo! Groups??

    - by Dion
    Hello all, Can anybody suggests me any extensions for Joomla that works like Yahoo!Groups?? I needed an extensions that : 1. If i post a new subject, everybody on the subscription list get that new subject/article/post on their e-mail. 2. The subscriber/receiver of that mail, can reply it directly from their e-mail (yahoo, gmail, outlook, etc)...and, their reply shows on the website front end. Basically, like Yahoo! Groups did... I've tried "Acajoom", and "Ultimate Mailing List"....both worked great for creating a newsletter, subscription, and sending mail to all the subscriber. But i cannot reply the e-mail and showed the reply on the website, and the other receiver didn;t receive it too...so there is absolutely no interaction within the mailing list. If anyone can suggest me something, i will be very grateful Thanx!!

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  • What makes the availability of both primitive and object-wrapped values in JavaScript useful?

    - by Delan Azabani
    I wrote a blog post a while ago detailing how the availability of both primitive and object-wrapped value types in JavaScript (for things such as Number, String and Boolean) causes trouble, including but not limited to type-casting to a boolean (e.g. object-wrapped NaN, "" and false actually type-cast to true). My question is, with all this confusion and problems, is there any benefit to JavaScript having both types of values for the built-in classes?

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  • How to include named capture groups in java regex?

    - by jrummell
    I'm new to regex in Java and I can't figure out how to include named capture groups in an expression. I'm writing a ScrewTurn Image Converter for Confluence's Universal Wiki Converter. This is what I have: String image = "\\[image(?<align>auto)?\\|\\|{UP\\(((?<namespace>\\w+)\\.)?(?<pagename>[\\w-]+)\\)}(?<filename>[\\w- ]+\\.[\\w]+)\\]"; Pattern imagePattern = Pattern.compile(image, Pattern.CASE_INSENSITIVE); It's throwing this exception in Pattern.comiple(): java.util.regex.PatternSyntaxException: Unknown look-behind group near index 19 \[image(?<align>auto)?\|\|{UP\(((?<namespace>\w+)\.)?(?<pagename>[\w-]+)\)}(?<filename>[\w- ]+\.[\w]+)\] ^ I've used named capture groups like this before in C# (?<namedgroup>asdf), but not in Java. What am I missing?

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  • How to group rows into two groups in sql?

    - by user1055638
    Lets say I have such a table: id|time|operation 1 2 read 2 5 write 3 3 read 4 7 read 5 2 save 6 1 open and now I would like to do two things: Divide all these records into two groups: 1) all rows where operation equals to "read" 2) all other rows. Sum the time in each group. So that my query would result only into two rows. What I got so far is: select sum(time) as total_time, operation group by operation ; Although that gives me many groups, depending on the number of distinct operations. How I could group them only into two categories? Cheers!

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  • SQL Server 2008 R2 installation Error "Not all privileges or groups referenced are assigned to the caller"

    - by CodeSlinger
    Im getting an error half way through an SQL Server 2008 r2 installation. The error states Not all privileges or groups referenced are assigned to the caller. it asks to retry or cancel. Upon trying both, the error message returns and I must cntrl-alt-delete to end the process. I have checked all permissions associated with local account, network domain account and ran installation as administrator. I have searched on the web and other people are having this problem too but I cant find a solution. so I turn to the experts, anyone encounter this error??

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  • How to Achieve Real-Time Data Protection and Availabilty....For Real

    - by JoeMeeks
    There is a class of business and mission critical applications where downtime or data loss have substantial negative impact on revenue, customer service, reputation, cost, etc. Because the Oracle Database is used extensively to provide reliable performance and availability for this class of application, it also provides an integrated set of capabilities for real-time data protection and availability. Active Data Guard, depicted in the figure below, is the cornerstone for accomplishing these objectives because it provides the absolute best real-time data protection and availability for the Oracle Database. This is a bold statement, but it is supported by the facts. It isn’t so much that alternative solutions are bad, it’s just that their architectures prevent them from achieving the same levels of data protection, availability, simplicity, and asset utilization provided by Active Data Guard. Let’s explore further. Backups are the most popular method used to protect data and are an essential best practice for every database. Not surprisingly, Oracle Recovery Manager (RMAN) is one of the most commonly used features of the Oracle Database. But comparing Active Data Guard to backups is like comparing apples to motorcycles. Active Data Guard uses a hot (open read-only), synchronized copy of the production database to provide real-time data protection and HA. In contrast, a restore from backup takes time and often has many moving parts - people, processes, software and systems – that can create a level of uncertainty during an outage that critical applications can’t afford. This is why backups play a secondary role for your most critical databases by complementing real-time solutions that can provide both data protection and availability. Before Data Guard, enterprises used storage remote-mirroring for real-time data protection and availability. Remote-mirroring is a sophisticated storage technology promoted as a generic infrastructure solution that makes a simple promise – whatever is written to a primary volume will also be written to the mirrored volume at a remote site. Keeping this promise is also what causes data loss and downtime when the data written to primary volumes is corrupt – the same corruption is faithfully mirrored to the remote volume making both copies unusable. This happens because remote-mirroring is a generic process. It has no  intrinsic knowledge of Oracle data structures to enable advanced protection, nor can it perform independent Oracle validation BEFORE changes are applied to the remote copy. There is also nothing to prevent human error (e.g. a storage admin accidentally deleting critical files) from also impacting the remote mirrored copy. Remote-mirroring tricks users by creating a false impression that there are two separate copies of the Oracle Database. In truth; while remote-mirroring maintains two copies of the data on different volumes, both are part of a single closely coupled system. Not only will remote-mirroring propagate corruptions and administrative errors, but the changes applied to the mirrored volume are a result of the same Oracle code path that applied the change to the source volume. There is no isolation, either from a storage mirroring perspective or from an Oracle software perspective.  Bottom line, storage remote-mirroring lacks both the smarts and isolation level necessary to provide true data protection. Active Data Guard offers much more than storage remote-mirroring when your objective is protecting your enterprise from downtime and data loss. Like remote-mirroring, an Active Data Guard replica is an exact block for block copy of the primary. Unlike remote-mirroring, an Active Data Guard replica is NOT a tightly coupled copy of the source volumes - it is a completely independent Oracle Database. Active Data Guard’s inherent knowledge of Oracle data block and redo structures enables a separate Oracle Database using a different Oracle code path than the primary to use the full complement of Oracle data validation methods before changes are applied to the synchronized copy. These include: physical check sum, logical intra-block checking, lost write validation, and automatic block repair. The figure below illustrates the stark difference between the knowledge that remote-mirroring can discern from an Oracle data block and what Active Data Guard can discern. An Active Data Guard standby also provides a range of additional services enabled by the fact that it is a running Oracle Database - not just a mirrored copy of data files. An Active Data Guard standby database can be open read-only while it is synchronizing with the primary. This enables read-only workloads to be offloaded from the primary system and run on the active standby - boosting performance by utilizing all assets. An Active Data Guard standby can also be used to implement many types of system and database maintenance in rolling fashion. Maintenance and upgrades are first implemented on the standby while production runs unaffected at the primary. After the primary and standby are synchronized and all changes have been validated, the production workload is quickly switched to the standby. The only downtime is the time required for user connections to transfer from one system to the next. These capabilities further expand the expectations of availability offered by a data protection solution beyond what is possible to do using storage remote-mirroring. So don’t be fooled by appearances.  Storage remote-mirroring and Active Data Guard replication may look similar on the surface - but the devil is in the details. Only Active Data Guard has the smarts, the isolation, and the simplicity, to provide the best data protection and availability for the Oracle Database. Stay tuned for future blog posts that dive into the many differences between storage remote-mirroring and Active Data Guard along the dimensions of data protection, data availability, cost, asset utilization and return on investment. For additional information on Active Data Guard, see: Active Data Guard Technical White Paper Active Data Guard vs Storage Remote-Mirroring Active Data Guard Home Page on the Oracle Technology Network

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