Neverfail for File Server: Unprotected Features of the Windows NTFS File System

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Summary

This Knowledgebase article provides information about unprotected features of the Windows NTFS file system.

More Information

The Microsoft Windows family of Operating Systems supports a number of features for which Neverfail for File Server does not offer protection. There are a variety of reasons for this, but in general, any feature whose presence might lead to corruption, loss of data, abnormal disk space usage, or other detrimental effects, on the passive server, is treated as an unprotected feature. Neverfail for File Server can be configured to respond to such features in a variety of ways, depending on the risk posed by each type of unprotected feature. By default, there are three responses:

  1. Warn, and Continue Replication

    AFFECTED FEATURES: Sparse files, disk quotas

    EXAMPLE: Sparse Files

    WARNING:

    - Unprotected Feature Detected [ Primary | Secondary ] (while active)

    - Sparse Files may not be replicated for the file / directory : C:\MyDirectory\SF\File1.txt.

    RESULT: Neverfail Heartbeat data replication continues, but the Sparse Files referred to in the warning message may not be replicated.

    RECOVERY: None required

  2. Log an Error, and Set the File System Status to 'Out of Synch'
    1. Either locally on the active server or on a remote client go to Start -> All Programs -> Neverfail -> Manage Server to open the Neverfail Heartbeat Management Client
    2. Navigate to Data: Replication .
    3. In the left-hand pane, identify any red folders.
    4. Select the parent of a red folder and the folder will appear in the right-hand (or middle) pane. If the folder representing an entire volume (e.g. C:, D:, E: etc) is shown in red, it may be necessary to select 'My Computer' as the parent folder in the left-hand pane, even if this is also flagged in red.
    5. In the right-hand (or middle) pane, select the red folder and click Synchronize . DO NOT choose the option to synchronize subdirectories.

    This strategy is used where replication of file content cannot be guaranteed, or where the file system might become 'Out of Synch' due to file access or locking issues on the passive (formerly active) server after a switchover. Neverfail Heartbeat will allow data replication to continue, but marks any affected files as 'Out of Synch' in order to prevent a switchover.

    AFFECTED FEATURES: Encryption, extended attributes

    EXAMPLE: ENCRYPTION

    ERROR:

    - Unprotected Feature Detected [ Primary | Secondary ] (while active)

    - Automated Out Of Synch Applied : Use of Encrypted Files has been detected for the file / directory :

    C:\MyDirectory\Encrypt\EncryptFolder

    As a result of this, the file/directory will be marked as Out Of Synch.

    RESULT: Neverfail Heartbeat data replication continues, but the File System status is set to 'Out of Synch'. Shared folders are still available on the active server.

    RECOVERY: The affected file(s)/folder(s) must be removed from the protected set to allow the file system to synchronize. Switchover will not be possible until this has been done, though failover can still take place if the active server fails. Use one of the methods below:

    • Method 1 (preferred) - Move all affected files to an unshared folder, or delete them.
    • Method 2 (alternate) - Using Windows Explorer, or any other suitable tool, un-share the affected folder(s) on the active server. This MUST be done while Neverfail Heartbeat is replicating.
    • Method 3 (alternate) - Copy the affected files to a FAT32 file system and then copy them back.
    • Method 4 (alternate) - Compacting/uncompacting those files into a .zip / .arg file.

      Note: If method 2 is used, it may be necessary to synchronize one or more files / folders manually afterwards. This can be done with the following procedure:

    Please refer to Neverfail Heartbeat product documentation for further information on synchronizing files and folders.

  3. Log an Error, and Stop Replication

    This is used where some file metadata may not be replicated to the passive server, but in all other respects, replication can continue unhindered, and near-normal service can be expected following switchover or failover. Note that file attributes (with the exception of the Encryption flag) and file permissions are not affected in this way, and will always be replicated.

    This strategy is used where data replication might lead to corruption of files on the passive server. Any subsequent switchover could corrupt the original data on the server that was active; and, in the event of a failover, there is a risk that the failed server could be recovered and reconnected in the passive role, and have its data overwritten with corrupted file content from the surviving server, now operating in the active role. The safest option here is to cease replication since, if replication is stopped, neither switchover nor failover can occur, allowing the issue to be resolved safely.

    AFFECTED FEATURES: Hard links, reparse points (volume mount points, directory junctions, symbolic links, single instance store, remote storage). Note that Windows 2003 DFS Reparse Points are NOT affected, as they are fully supported by Neverfail Heartbeat from V4.3 onwards.


    EXAMPLE: HARD LINKS

    ERROR (1):

    - Unprotected Feature Detected [ Primary | Secondary ] (while active)

    - Automated Replication Stop Applied : Use of Hard Links has been detected for the file / directory :

    C:\MyDirectory\HardLinkFile1

    As a result of this, Neverfail Heartbeat has been stopped with the protected applications left running.

    ERROR (2):

    - System Stop [ Primary | Secondary ] (while active)

    - Neverfail Heartbeat is stopping (without stopping the protected applications) for the following reason :

    Automated Replication Stop Applied : Use of Hard Links has been detected for the file / directory :

    C:\MyDirectory\HardLinkFile1

    As a result of this, Neverfail Heartbeat has been stopped with the protected applications left running.

    RESULT: Neverfail Heartbeat data replication stops, but shared folders are still available on the active server.

    RECOVERY: The affected file(s) / folder(s) must be removed from the protected set before replication can be restarted. Use one of the methods below to accomplish this:

    • Method 1 (preferred)

      1. Move all affected files to an unshared folder, or delete them.
      2. Start replication by using the Neverfail Heartbeat Management Client. Navigate to Server: Summary and click Start Replication .
      3. Wait until both 'File System Status' and 'Registry Status' show as 'Synchronized'.
    • Method 2 (alternate)
  4. Manually delete the filter for the file(s) / folder(s) identified in the error message.

    1. To do this, either locally on the active server or on a remote client, go to Start -> All Programs -> Neverfail -> Manage Server to open the Neverfail Heartbeat Management Client.
    2. Navigate to Data: File Filters .
    3. Select the filter to be deleted, and click Delete .
    4. Repeat for all affected filters.

    Start replication

    1. Using the Neverfail Heartbeat Management Client, navigate to Server: Summary and click Start Replication .
    2. Wait until both 'File System Status' and 'Registry Status' show as 'Synchronized'.

    Using Windows Explorer, or any other suitable tool, un-share the affected folder(s) on the active server. This MUST be done while Neverfail Heartbeat is replicating. If method 2 is used, it may be necessary to synchronize one or more files / folders manually afterwards. To do this, follow the procedure below:

    1. Either locally on the active server or on a remote client go to Start -> All Programs -> Neverfail -> Manage Server to open the Neverfail Heartbeat Management Client.
    2. Navigate to Data -> File Synch And Verify .
    3. In the left-hand pane, identify any red folders.
    4. Select the parent of a red folder and the folder will appear in the right-hand (or middle) pane.
    5. If the folder representing an entire volume (e.g. C:, D:, E: etc) is shown in red, it may be necessary to select 'My Computer' as the parent folder in the left-hand pane, even if this is also flagged in red.
    6. In the right-hand (or middle) pane, select the red folder and click Synchronize .

    Note: DO NOT choose the option to synchronize subdirectories. Please refer to Neverfail Heartbeat product documentation for further information on synchronizing files and folders.

  5. Summary - Reference Information
ID Name LogAsError MakeOutOfSync MaxOccurrences RaiseStopEvent RaiseUserEvent
0 Extended Attributes True True 100 False True
1 Hard Link True False 100 True True
2 Hard Link Mismatch True False 100 True True
3 Reparse Point True False 100 True True
4 Encryption True True 100 False True
5 Sparse File True False 100 False True
6 Disk Quota True False 100 False True

Applies To

Windows NTFS File System


Related Information

None

KBID-321

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