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arcserve-KB : Users unable to access files during CA XOsoft Synchronization.

Last Update: 2015-12-15 22:08:02 UTC

XOSOFT Replication: 12.0, 12.5
Last Modified Date:    03/15/2010
Document ID:    TEC510200
Tech Document
Title:  Users unable to access files during CA XOsoft Synchronization.

Description:

You are running a CA XOsoft r12.x for File Server scenario configured to use File Synchronization. After starting your CA XOsoft r12.x scenario users connecting to shares report that they cannot access files. Once the CA XOsoft synchronization process completes, user access is restored. Access is also restored as soon as the CA XOsoft scenario is stopped.

Solution:

CA XOsoft r12.x uses Microsoft Volume Shadow Copy Service (VSS) to execute the compare process during synchronization. This allows CA XOsoft to accurately compare the data on the Master and Replica servers, avoiding the need to lock to the file system.

If users are reporting that they are unable access shares during synchronization, then one or more of the following could be the cause:

  1. Your Master and/or Replica server is running a version of Windows Server older than Windows Server 2003.

    • Microsoft only introduced Volume Shadow Copy Service (VSS) in Windows Server 2003. Windows Server 2000 doesn't support VSS, therefore on a server running Windows Server 2000, CA XOsoft must revert to the older method of 'File Scan' used by older versions of CA XOsoft when File Synchronization is configured. The older 'File Scan' method needs to lock the file system in order to complete an accurate compare and ensure data integrity on the replica as a result of the compare process.

    SOLUTION #1: Upgrade to Windows Server 2003 or later. MS Windows Server 2003 and higher includes VSS which will allow CA XOsoft to utilize VSS for comparison instead of the 'File Scan' method used in older versions of CA XOsoft and on older Operating Systems. VSS alleviates the need to lock the file system during the compare process.

  2. You are running a version of CA XOsoft older than r12.x.

    • The use of VSS to execute the compare process was only introduced in CA XOsoft r12.0 and continues in r12.5. CA XOsoft V4.x and older (WANSync) do not utilize VSS. Instead they employ the older 'File Scan' method of compare when File Synchronization is configured. The older 'File Scan' method of compare needs to lock the file system in order to complete an accurate compare and ensure data integrity on the replica as a result of the compare process.

    SOLUTION #2: Upgrade to CA XOsoft r12.0 or higher. CA XOsoft r12.0 and higher utilize VSS snapshots for the comparison of files when File Synchronization is configured. VSS alleviates the need to lock the file system during the compare process.

  3. CA XOsoft r12.x is running on Windows Server 2003 (or higher). The scenario is configured to protect a Database application (e.g. MS Exchange, MS SQL, Oracle, etc). The scenario is configured to use Block Synchronization. The scenario (e.g. MS Exchange, MS SQL, Oracle) also contains root directories for file shares. Users don't report any issues accessing the database application, however they are prevented from accessing files on shares which are being connected to using mapped drives (UNC paths) on the same server. Only the share data is inaccessible.

    • All versions of CA XOsoft (including WANSync) up to r12.5, are configured to use one of two methods of comparison; Block Synchronization or File Synchronization. The default method of comparison used for database applications (e.g. MS Exchange, MS SQL, Oracle, etc) is Block Synchronization. Block Synchronization is optimized for databases or a large small selection of relatively large files. This method does not need to lock the file system. File Synchronization is the default for File Servers, where there is typically a large collection of relatively small files. When a scenario is configured to use Block Synchronization, if there are additional directories and files defined for replication in addition to the directories added through the 'Auto-Detect Databases', then those directories will default to the 'File Scan' method of comparison which does not use VSS. The Block Synchronization compare is used on the Database directories, however the 'File Scan' method of compare is used on the additional files, not VSS. This causes a situation where the access to the additional files on the file system are locked during the 'File Scan' compare process. XOsoft cannot be configured to use VSS in conjunction with Block Synchronization. File Synchronization cannot be used on database servers.

    SOLUTION #3: Create 2 Scenarios. Create a CA XOsoft scenario for the Databases, and a second scenario for the additional directories and files. Configured the database application scenario to use Block Synchronization. This can be either an HA or a DR scenario. Configure the replication of the additional files in a File Server DR scenario which will be configured to use File Synchronization. The scenario protecting the databases will use Block Synchronization and the scenario protecting the additional files will use File Synchronization and will use VSS to alleviate the locking of the file system during the compare process of synchronization.

  4. CA XOsoft version is r12.x. The servers defined in the scenario are MS Windows Server 2003 or higher. The scenario is configured to use File Synchronization and the users are still reporting that the directories are inaccessible during the CA XOsoft Synchronization process.

    SOLUTION #4: Make sure the 'Volume Shadow Copy' service in the Services.msc is not Disabled. The service should be set to either Automatic or Manual.

  5. CA XOsoft version is r12.x. The servers defined in the scenario are MS Windows Server 2003 or higher. The scenario is configured to use File Synchronization. The Volume Shadow Copy Service is configured with either a Manual or Automatic startup type, and is not disabled. The users are still reporting that the directories are inaccessible during the CA XOsoft Synchronization process.

    When you review the Windows Application logs you see errors similar to the following:
    Event Type: Error
    
    Event Source: VSS
    
    Event Category: None
    
    Event ID: 12292
    
    Date:  9/9/2009
    
    Time:  10:10:58 PM
    
    User:  N/A
    
    Computer: <Server Name>
    
    Description:
    
    Volume Shadow Copy Service error: Error creating the Shadow Copy Provider COM class with CLSID {819e04d3-809b-4657-aee0-778ca24470da} [0x8007042c].
    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
    Data:
    
    0000: 2d 20 43 6f 64 65 3a 20   - Code: 
    
    0008: 43 4f 52 48 57 50 57 43   CORHWPWC
    
    0010: 30 30 30 30 30 33 30 36   00000306
    
    0018: 2d 20 43 61 6c 6c 3a 20   - Call: 
    
    0020: 43 4f 52 48 57 50 57 43   CORHWPWC
    
    0028: 30 30 30 30 30 32 34 32   00000242
    
    0030: 2d 20 50 49 44 3a 20 20   - PID:  
    
    0038: 30 30 30 30 32 34 39 32   00002492
    
    0040: 2d 20 54 49 44 3a 20 20   - TID:  
    
    0048: 30 30 30 30 32 36 30 38   00002608
    
    0050: 2d 20 43 4d 44 3a 20 20   - CMD:  
    
    0058: 43 3a 5c 57 49 4e 44 4f   C:\WINDO
    
    0060: 57 53 5c 53 79 73 74 65   WS\Syste
    
    0068: 6d 33 32 5c 76 73 73 76   m32\vssv
    
    0070: 63 2e 65 78 65 20 20 20   c.exe   
    
    0078: 2d 20 55 73 65 72 3a 20   - User: 
    
    0080: 4e 54 20 41 55 54 48 4f   NT AUTHO
    
    0088: 52 49 54 59 5c 53 59 53   RITY\SYS
    
    0090: 54 45 4d 20 20 20 20 20   TEM     
    
    0098: 2d 20 53 69 64 3a 20 20   - Sid:  
    
    00a0: 53 2d 31 2d 35 2d 31 38   S-1-5-18
    Event Type: Error
    
    Event Source: VSS
    
    Event Category: None
    
    Event ID: 12293
    
    Date:  9/9/2009
    
    Time:  10:16:07 PM
    
    User:  N/A
    
    Computer: BOSUSERDATA2
    
    Description:
    
    Volume Shadow Copy Service error: Error calling a routine on the Shadow Copy Provider {ddd3d232-a96f-4ac5-8f7b-250fd91fd102}. 
    
    Routine details CommitSnapshots({d6c2d8b5-4750-4ff5-ba2c-5e477d7e2ffd}) [hr = 0xc0040307].
    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
    Data:
    
    0000: 2d 20 43 6f 64 65 3a 20   - Code: 
    
    0008: 43 4f 52 53 4e 50 53 43   CORSNPSC
    
    0010: 30 30 30 30 31 33 37 35   00001375
    
    0018: 2d 20 43 61 6c 6c 3a 20   - Call: 
    
    0020: 43 4f 52 53 4e 50 53 43   CORSNPSC
    
    0028: 30 30 30 30 31 33 36 31   00001361
    
    0030: 2d 20 50 49 44 3a 20 20   - PID:  
    
    0038: 30 30 30 30 33 38 34 34   00003844
    
    0040: 2d 20 54 49 44 3a 20 20   - TID:  
    
    0048: 30 30 30 30 30 36 30 34   00000604
    
    0050: 2d 20 43 4d 44 3a 20 20   - CMD:  
    
    0058: 43 3a 5c 57 49 4e 44 4f   C:\WINDO
    
    0060: 57 53 5c 53 79 73 74 65   WS\Syste
    
    0068: 6d 33 32 5c 76 73 73 76   m32\vssv
    
    0070: 63 2e 65 78 65 20 20 20   c.exe   
    
    0078: 2d 20 55 73 65 72 3a 20   - User: 
    
    0080: 4e 54 20 41 55 54 48 4f   NT AUTHO
    
    0088: 52 49 54 59 5c 53 59 53   RITY\SYS
    
    0090: 54 45 4d 20 20 20 20 20   TEM     
    
    0098: 2d 20 53 69 64 3a 20 20   - Sid:  
    
    00a0: 53 2d 31 2d 35 2d 31 38   S-1-5-18
    When you review the CA XOsoft logs you see the following errors:
     Querying all shadow copies in the system ...
    
     (12/7/2009 9:48:36 PM) error-> Unable to Query shadow copies in the system. Error code: 0x8004230F
    
     (12/7/2009 9:48:36 PM) - Setting the VSS context to: 0xffffffff
    
     (12/7/2009 9:48:36 PM) Querying all shadow copies in the system ...
    
     (12/7/2009 9:48:36 PM) error-> Unable to Query shadow copies in the system. Error code: 0x8004230F
    
     (12/7/2009 9:48:36 PM) error-> Unable to create shadow copy storage area for volume [E:\] on volume [E:]. Unknown error.  (0x00000009)
    
     (12/7/2009 9:48:37 PM) - Setting the VSS context to: 0x00020019
    
     (12/7/2009 9:48:37 PM) server is set to use microsoft VSS provider for snapshots creation
    
     (12/7/2009 9:48:37 PM) Trying to check whether MS VSS provider supports the volume \\?\E:\
    
     (12/7/2009 9:48:37 PM) error-> Unable to check if the specified volume is supported by the VSS default provider. The provider returned an unexpected error code. (0x8004230f)
    
     (12/7/2009 9:48:37 PM) unable to use VSS snapshot for synchronization, continue using file system scan
    SOLUTION #5: Download and apply Microsoft Patch: 940349. (http://support.microsoft.com/kb/940349/). This is an update rollup package is available to resolve some Volume Shadow Copy Service (VSS) snapshot issues in Windows Server 2003.
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