Sometimes Data Protector CBT backups of a certain VM fail.
[Normal] From: VEPALIB_VMWARE@rz3602.gewkoelnag.de "" Time: 06/01/2016 02:17:12 PM
Virtual Machine 'instp1.re-rz.de': Backing up configuration file instp1.re-rz.de.vmx ...
[Normal] From: VEPALIB_VMWARE@rz3602.gewkoelnag.de "" Time: 06/01/2016 02:17:14 PM
Virtual Machine 'instp1.re-rz.de': Creating snapshot ...
[Critical] From: VEPALIB_VMWARE@rz3602.gewkoelnag.de "" Time: 06/01/2016 02:17:20 PM
Backup failed because unable to utilize CBT as it was required.
This might be a Vmware limitation.
In such a case it is always good idea to double check if the prerequisites for CBT are fulfilled.
https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1020128
Changed Block Tracking (CBT) on virtual machines (1020128)
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For CBT to identify altered disk sectors since the last change ID, these items are required:
• The host must be ESX/ESXi 4.0 or later.
• The virtual machine owning the disks to be tracked must be hardware version 7 or later.
• I/O operations must go through the ESX/ESXi storage stack. So NFS is supported, as is RDM in virtual compatibility mode, but not RDM in physical compatibility mode. VMFS is supported, whether backed by SAN, iSCSI, or local disk.
• CBT must be enabled for the virtual machine (see below).
• Virtual machine storage must not be (persistent or non-persistent) independent disk, meaning unaffected by snapshots.