Using VMware's Changed Block Tracking for full backups only


Using VMware's Changed Block Tracking for full backups only

This topic applies to NetBackup for VMware.

The Enable block-level incremental backup option (BLIB) in the NetBackup VMware policy applies to full backups and incremental backups. BLIB skips blocks on the virtual disk that are unmodified since the last backup. If you want to skip unmodified blocks during full backups but not incrementals, do not configure the policy for BLIB. Instead, enable changed block tracking by means of the vSphere Client interface.

More information is available on BLIB.

See Block-level backup (BLIB): full vs incremental.

To enable changed block tracking for full backups only (vSphere Client interface)

  1. In the vSphere Client interface, power off the virtual machine.

  2. Select the virtual machine, then click Edit settings.

  3. Obtain the hard drive controller and disk numbers (SCSI and IDE) for each virtual drive on the virtual machine.

    To find the controller number and disk numbers, do the following:

    • Click the Hardware tab.

    • Click on each hard disk. Its controller number and disk number (SCSI or IDE) appear under Virtual Device Node, in the form SCSI(X.X) or IDE(X.X). Make a note of each.

  4. Click the Options tab. Under Advanced, General, click Configuration Parameters.

  5. On the Configuration Parameters screen, click Add Row.

  6. Enter ctkEnabled in the Name column and enter true for the Value.

  7. For each virtual drive on the virtual machine, enter a Name in the form:




    where X:X represents the controller number and disk number of each disk as found on the Hardware tab.

    For example: scsi0:0.ctkEnabled for the first disk and scsi0:1.ctkEnabled for the second disk. (The numbers for your disks may be different.)

  8. Enter true for the Value of each disk entry.

  9. Click OK.

  10. Power on the virtual machine.

    Now you can use vSphere Client to take a snapshot of the virtual machine. NetBackup can apply vStorage optimization (changed block tracking) to future backups of the virtual machine.

See About reducing the size of VMware backups

Terms of use for this information are found in Legal Notices.



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