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Druva Documentation

How to query CBT outside of Phoenix when VM backups fail with CBT errors

This article applies to:

  • OS: ESXi
  • Product edition: Phoenix Cloud


This article describes the procedure to use the vSphere Managed Object Browser (MOB) to execute a query on CBT outside of Phoenix to verify if CBT is functioning correctly. This article can assist Technical Support Engineers to troubleshoot CBT errors that occur during the backup of virtual machines.   

Query CBT using MOB

Prerequisite: At least one snapshot of the VM under test must be backed up through the backup software or manually.

  1. Since the MOB is disabled by default on vSphere 6.0, enable the access to MOB as follows:
    1. Select ESXi host in vSphere and navigate to the Configuration tab and select Advanced settings.

    2. Expand Config > HostAgent > plugins > solo and select Config.HostAgent.plugins.solo.enableMob.
  2. Open https://ipaddress_of_your_ESXi_hot/mob in a browser.
  3. Enter the root credentials to access the ESXi host.
  4. Select the content value in the Service Instance Managed Object Type.

  5. Search for "rootFolder " under properties and select "ha-folder-root".

  6. Search the "childEntity" under properties and click "ha-datacenter".

  7. Search for datastore under properties and select the datastore that contains the VM that needs to be tested.

  8. Search the VM property value. From the VM names displayed, select the required VM.

  9. Copy the value name of "rootSnapshot".

  10. Scroll down and under Methods , click "QueryChangeDiskAreas" in DiskChangeInfo value.

  11. Enter the following values on the DiskChangeInfo QueryChangedDiskAreas window.
    Parameter: snapshot: Replace MOID with the value copied before (for example: 59-snapshot-81)
    Parameter: deviceKey:
                                                      To query the first vmdk file, enter: 2000
                                                       To query the second vmdk file, enter: 2001
    Parameter: StartOffset: Enter: 0
    Parameter: changed: Enter: *

  12. Select Invoke Method after entering the values.
    If CBT works correctly, the Method Invocation Result: DiskChangeInfo and associated values are displayed.

    If CBT is not enabled, the following result is displayed.