Just a short notice if you are already on ESXi 6:
There is an issue with Change Block Tracking (CBT) in Express Patch 6 for ESXi 6 (Build 3825889) that can affect your backup if your backup software relies on CBT.
- affected are only VMs with Operating System Server 2008 or newer (Linux VMs are unaffected.)
- all vHW Versions (7, 8, 9, 10 and 11) and all VMware tools versions are affected
- the issue occurs with thick and thin provisioned disks
- the issue only occurs when the backup software uses quiesced snapshots
Error messages:
You can find errors in the vmware.log of the affected VMs similar to:
vcpu-0| I120: SNAPSHOT:SnapshotBranchDisk: Failed to acquire current epoch for disk /vmfs/volumes/
vmdk : Change tracking is not active for this disk 572.
Other symptoms:
- you have to backup an abnormal amount of data (it is almost a full backup even if it is an incremental one)
- longer backup durations due to the abnormal amount of data sent to the backup software
Resolution:
There are currently 2 workarounds available:
- don’t use quiesced (application-aware) snapshots
- Revert to a previous version of ESXi, e.g. vSphere ESXi 6 U2 (build 3620759) (https://kb.vmware.com/kb/1033604)
If you already have affected virtual machines, migrate them to a host using an unaffected ESXi version (eg. VMware ESXi 6 Update 2, build 3620759).
Then you have to reset CBT of the affected VMs and perform a Full Backup to ensure that your backup is reliable.
Additional information:
- VMware VDP seems to be affected by the issue
- IBM TSM seems to be affected by the issue
- Veeam Backup & Replication seems not to be affected as long as you do not enable VMware Tools quiescence (in the backup job settings):
Der Beitrag Take care – Express Patch 6 for ESXi 6 can break your Backup (CBT Bug)! erschien zuerst auf All about virtualization.