What to do with VM with the CBT feature disabled ?

[albertwt]

Hi,

I've noticed that there are at least 25-30 % of my VMs does not have the CBT feature enabled when running the following Powershell script:

Code: Select all

https://github.com/alanrenouf/vCheck-vSphere

So I wonder if I should do something about it or does Veeam can automatically set the feature to be on ?
or is there any reason as to why the specific VM on the list above must not use CBT ?

Any kind of help and suggestion would be greatly appreciated.

Thanks,

[VladV]

CBT is disabled by default and gets enabled automatically when the VM is processed by Veeam and the option "Enable CBT for all protected VMs automatically" is selected in the Backup or Replication job.

CBT is used to enable the backup software do a real incremental run by mapping the modified blocks in a timeline, si it will read only those blocks on incremental runs.

As to whether or not those specific VMs should have CBT disabled is only up to you, but I can't see how CBT would have a negative impact on them.

[albertwt]

CBT is disabled by default and gets enabled automatically when the VM is processed by Veeam and the option "Enable CBT for all protected VMs automatically" is selected in the Backup or Replication job.

CBT is used to enable the backup software do a real incremental run by mapping the modified blocks in a timeline, si it will read only those blocks on incremental runs.

As to whether or not those specific VMs should have CBT disabled is only up to you, but I can't see how CBT would have a negative impact on them.

So yeah, that's what I thought before. I'm not sure as to why those VMs is not automatically set CBT enabled by Veeam ?

[VladV]

Are they included in a backup or replication job?

[albertwt]

Are they included in a backup or replication job?

yes they are.

[VladV]

Are they proxies used by VBR? I noticed that those VMs aren't processed using CBT and no warning or errors are logged.

[albertwt]

Are they proxies used by VBR? I noticed that those VMs aren't processed using CBT and no warning or errors are logged.

No those VMs are not VBR proxies.

[Vitaliy S.]

Do you have this checkbox turned on " Enable changed block tracking for all processed VMs"? See our online helpcenter web page for more info > http://helpcenter.veeam.com/backup/70/v ... ghtsub=CBT

[joergr]

Hmmmmm.....COULD it be your VM Hardware Version is less than 7? That would explain it.

CBT needs minimum HW7. If B+R finds a hardware version less, it will simply not use cbt. Very simple

[albertwt]

Hmmmmm.....COULD it be your VM Hardware Version is less than 7? That would explain it.

CBT needs minimum HW7. If B+R finds a hardware version less, it will simply not use cbt. Very simple

Is it v8 or 9 that is not automatically enabled ?

[joergr]

Albert,

please read http://kb.vmware.com/selfservice/micros ... Id=1020128
especially "The virtual machine owning the disks to be tracked must be hardware version 7 or later".

Best regards,
Joerg

[albertwt]

Cool, thanks !