How to Extend the Disk Space of an Existing Shared Disk with Windows Clustering

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This article discusses how to extend the disk space of a hardware-defined disk with Windows Clustering. If you add additional space to an existing cluster server disk at the hardware level, you must perform additional steps to ensure that the computer system recognizes this additional disk space.

For additional information about Windows 2000 Clustering, click the article number below to view the article in the Microsoft Knowledge Base:
304736 How to Extend the Partition of a Cluster Shared Disk
To add disk space to an existing cluster server disk at the hardware level, use either of the following methods.

Method 1: Create a New Partition on the Current Physical Disk

For additional information about how to create a new partition on the current physical disk, click the article number below to view the article in the Microsoft Knowledge Base:
175278 How to Install Additional Drives on the Shared SCSI Bus

Method 2: Delete the Current Partition and Create a New Partition

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows

You can delete the existing partition and create a new partition that includes all available disk space. To do this, follow these steps:
  1. On node 2, change the startup value to Manual for the following items:
    • Clusdisk (located in the Devices tool in Control Panel)
    • Cluster Service (located in the Services tool in Control Panel)
  2. Restart node 2.
  3. When the OS Loader Boot menu is displayed, press SPACEBAR. This procedure prevents Microsoft Windows NT from loading.

    NOTE: This procedure is necessary to maintain termination on the shared SCSI bus on some hardware configurations.
  4. On node 1, change the startup value to Manual for the following items:
    • Clusdisk (located in the Devices tool in Control Panel)
    • Cluster Service (located in the Services tool in Control Panel)
    NOTE: Do not attempt to stop the Clusdisk resource. If you do, you may receive the following error message:
    Error 2191: The requested pause or stop is not valid for this service.
  5. Restart node 1.IMPORTANT: By this step, you must have taken the necessary steps, as outlined by your hardware vendor, to extend the existing disk space at the hardware level.

  6. Back up all of the information on the shared disk that is to extended. You must verify that the backup is complete and accurate.

    CAUTION: After you extend the volume, all data is destroyed and you need a complete backup to restore any data.
  7. Delete all the partitions on the shared disk to be extended.
  8. Create a new partition that uses up all of the free space on the shared disk, format the disk with the NTFS file system, and then give the disk the same drive letter that the previous disk had.
  9. Restore all data to the shared disk.
  10. After you verify that the data is correctly restored, run the Regedt32.exe file.
  11. Locate HKey_Local_Machine. On the drop-down Registry menu, click load hive. On the Open dialog box, browse to \%System_root%\Cluster, and then click the Clusdb file. Open the file and when it prompts you for a name for the registry key, name it "cluster" (without the quotes).
  12. Expand the cluster hive, locate and expand the Resources key. A list of resources with global universal identification (GUID) is displayed. Click the first GUID. On the right-hand side of the screen is information about this GUID. Continue to click the GUIDs until you find the one for the disk that you just extended (the "type" shows the physical disk and the "name" tells you what disk you are looking at).
  13. When you locate the disk that you extended, expand the GUID key for that disk. A Parameters key is located under the GUID key. When you click the Parameters key, the right side of the screen has two values: a Diskinfo key and a Signature key. Click the Diskinfo key on the right side, and then delete it.

    IMPORTANT: Do not delete the Signature key.
  14. Go back to the root of the cluster hive and click the drop-down Registry menu, and then click unload hive. It may tell you that the key and all of its subkeys are to be removed. This message is normal behavior.
  15. Close the Regedt32.exe file.

    Locate CLUSDB in the c:\winnt\cluster directory and copy to a floppy or other location available to both nodes (not the shared disks).
  16. Start the Explorer.exe program and browse to your Quorum drive. Locate the MSCS folder on your quorum drive. There may be one or more files in the MSCS directory named Chk***.tmp. Rename all the .tmp files in the MSCS folder (you can delete them if you want to, but it is safer to rename them).
  17. Manually start the cluster disk device and reset its startup value back to "system".
  18. Manually start the Cluster Service and reset its startup value to "automatic".
  19. Open Cluster Administrator on your computer to verify that all of the resources are online.

    • Shutdown Node 1.
    • Boot Node 2.
    • Verify in Disk Administrator the recreated partition has the correct drive letter based on Step #8 above.
    • COPY CLUSDB into the c:\winnt\cluster directory from the floppy or other location used in step 15a above.
    • Change Start values back to defaults, do not start:

      a. Cluster disk device - reset its startup value back to "system".
      b. Cluster Service - reset its startup value to "automatic".
  20. Shutdown Node 2, Reboot Node1. Everything should continue to work.
  21. If all of the resources are online, turn on node 2.
  22. Fail the resource group that contains the newly extended disk back and forth between the cluster nodes to verify that it comes online on either node.
This behavior is by design.
IMPORTANT: This article assumes that the disk signature has not changed. If the "container" or physical disk has been deleted and recreated it will have a new disk signature. To handle new disk signatures, follow the procedure in:
243195 Event ID 1034 for MSCS Shared Disk After Disk Replacement
Some hardware-defined disks can have their allotted space increased without the loss or the restoration of any data that already exists on the disks. When this type of disk has its allotted space increased at the hardware level, your computer's operating system shows that additional free space now exists at the end of the disk. However, your computer's operating system does not show that the existing partition on the disk has actually been extended.

One method to extend a partition is to create a software volume set made up of the previous disk space and the newly added space which ensures that you can extend the current partition to include the newly added disk space. On a Windows Clustering server, however, the preceding method is not a valid option because Windows Clustering does not support software fault tolerant sets.

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
171052 Software FT Sets Are Not Supported in Microsoft Cluster
237853 Dynamic Disk Configuration Unavailable for Server Cluster Disks

Article ID: 263590 - Last Review: 12/05/2015 20:24:07 - Revision: 1.3

Microsoft Windows NT Server 4.0 Enterprise Edition

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