CBT data invalid on some VMs after upgrade to vSphere 6

[sdsohotech]

Here's my experience with the vmware 6 CBT bug so far:

We upgraded from ESX/vcenter5.5 to 6.0 in early October because my client got a new 6.0 upgrade license from Essentials Plus to Standard. Other than having to manually embed the HP b320i drivers into a custom ISO, it went well enough (drivers were not an issue on the 5.5 HP ISO).

It seemed like the backups were working OK after the upgrade. I would have noticed a 7 hour incremental vs a 15 minute incremental. In early November we set up a cluster and HA in vcenter (it was a simple datacenter setup before). After the cluster setup, I started getting CBT data is invalid on 4 VMs every time the backup ran. I tried running fulls and manually clearing out the CBT data. Sometimes it would fix the issue for a couple days on those VMs, and sometimes not. The issue would keep happening on those 4 VMs (out of 13 VMs).

Last night I downgraded the 3 hosts to 5.5, and left vcenter at 6.0. Reconfigured Veeam and the backup jobs. The new active full just finished a little while ago and I ran an incremental. There was 1 VM that had CBT data invalid, and it was the Veeam VM that I converted P2V at the same time we set up the cluster, so who knows what the root cause is exactly. I am going to remove the Veeam VM from the backup set and run a few more incrementals to see what happens. I'm pretty cranky about it because it's totally screwing up the backup window and the offsite copy job.

[sdsohotech]

I removed the Veeam VM from the main backup job and ran an incremental 3 times and CBT seems OK (for now at least). I will continue to monitor and see if the CBT issue returns. The Veeam VM is now set up on a separate job that only runs once a week, an active full, and CBT disabled.

I already have an open case with Veeam support for this, but nobody really knows what to do at this point.

[Gostev]

Jason, I've split your posts from the original topic since the issue your are dealing with is completely unrelated to the one that is being discussed there. Thanks!

[sdsohotech]

Got it. Thanks!