Was CBT disabled on backup proxies?

[averylarry]

[FIXES] v6 Known Issues and Patches
Issue 17

Does it really say that CBT cannot be used on the backup proxy VMs? If so, is this a temporary change? My 5 minute CBT backup has changed into 2 1/2 hours now for 1 VM and 1 hour for another.

[Jfmoots]

To me, it is saying any VM that is being used as a backup proxy will have CBT disabled. Not all VMs.

[averylarry]

That's what I meant. My backup proxy VM used to take 5 minutes using CBT and now it takes 2 1/2 hours without CBT. Non backup proxy VMs process normally with CBT.

[tsightler]

Yes, as a workaround for the hotadd CBT "stall" all backup proxies now have CBT disabled automatically. I don't know if there is a way to change this behavior if you were not having CBT "stall" issue during hotadd, but it would be nice, as disabling CBT for proxies works against customers who were using existing VMs as their proxy servers. It's much less of an issue for customers using dedicated proxies as those VMs are typically not worth backing up anyway and even if you want to back them up they are small.

[foggy]

Actually, no way to change this behavior currently (no registry key, etc).

[Gostev]

CBT is only disabled for backup proxies servers using hot add processing mode. For example, if your virtual backup proxy uses Direct SAN (via software iSCSI), or Network processing modes, B&R will not disable CBT on this VM.

Having CBT enabled on hot add proxy causes too much havoc and failures on backup jobs, this has been one of the top support cases for v6, so you definitely do not want to enable that.

[peabitty]

I know this is an old thread, but I have a question regarding this exact issue. Can we re-enable CBT processing in Veeam if a VM was a proxy at one point and we removed the proxy services from it? Do we just disable and enable CBT using the methods in this kb? https://www.veeam.com/kb1113

[foggy]

Hi Matt, just enable CBT manually on this VM and it will be backed up using CBT during the next job run.

[Tos]

Hi, I want to backup Veeam Server and Proxy Server.
These server is VM on vSphere6. So I can backup it by using Veeam. But Veeam can't use CBT for these VM with netowork mode. Veeam can use CBT for these VM on vSphere5.5.
I opened a case No.01715120. But I don't know whether Veeam use CBT for VM that Veeam install proxy component on vSphere 6…
Using ESXi version is 6.0 Build "3018523". So I think the known issues with CBT pre ESXi 6.0 Build 2715440 is resolved.
I did CBT reset of these VM and ran Active Full backup.
But this behavior still occur…
I want to use CBT for VM that Veeam install proxy component on vSphere 6 if possible.

[veremin]

Has this machine been ever used as Hot Add proxy? If yes, the absence of CBT is expected. Thanks.

[Vitaliy S.]

If you're using network processing mode, then CBT should be used. What is the exact error message for this proxy VM?

[Tos]

Hi
This proxy VM is never used as Hot Add proxy.
The following message in action log is outputted.
"CBT data is invalid, failing over to legacy incremental backup. No action is required, next job run should start using CBT again. If CBT data remains invalid, follow KB1113 to perform CBT reset. Usual cause is power loss. "
This behavior happens in vSphere6 only.
In vSphere5.5, CBT can be used for proxy VM.

[Vitaliy S.]

Ah...so it is not disabled, but invalid. Let's wait what your engineer finds out after investigating log files, as this message shouldn't be displayed after resetting CBT data and running active full backup.

[Tos]

Hi Vitaliy
Sure, I await the results of investigation.

[Vitaliy S.]

While you're waiting can you please create a new job (as a test) for this VM and see if CBT is used or not?

[Tos]

Hi,
I don't reproduced this behavior after applying the latest patch (build 3568940) .
I find the following VMware KB and the CBT issue resolved build 3247720 !
So the cause might be VMware side…
Thanks for the advice.