Forum Discussion

Level 4

9 years ago

cbt enabled by Netbackup?

Hi all,

I have a question about Accelerator and cbt option on vm machine.

This option is disabled, Can Netbackup enabled automatically if I have accelerator on vmware policy? And in this cas NETBACKUP poweroff vm?

Thanks a lot

nbutech
Level 6
9 years ago
Please check this technote and see if this answers your queries

Accelerator notes and requirements for virtual machines

https://www.veritas.com/support/en_US/article.HOWTO92075
sdo
Moderator
9 years ago
Yes, NetBackup will auto-enable CBT for the VM being backed-up... IF... the backup policy has block level incremental selected:

https://www.veritas.com/community/blogs/nuts-and-bolts-netbackup-vmware-avoiding-cbt-penalty-netbackup-accelerator
Rick80
Level 4
9 years ago
Hi sdo,

ok and without restart vm?

Thanks a lot

Rick
sdo
Moderator
9 years ago
NetBackup will not power-off the VM if/when it enables CBT.

The next VM stun/unstun cycle will effectively enable CBT.

A 'snapshot' event is a 'stun/unstun' event.

http://itknowledgeexchange.techtarget.com/virtualization-pro/what-is-changed-block-tracking-in-vsphere/

So, NetBackup will call the VMware API SDK to enable CBT, and then NetBackup will call the VMware API SDK to take a snapshot which will stun/unstun the VM.
So, NetBackup will not stop/restart the VM, and there should be no need to stop/restart the VM.
Rick80
Level 4
9 years ago
Hi STO,

Very good, but when backup is ended and snapshot was deleted, does it mean the cbt was disabled e re-enabled in the next snapshot?

Thanks a lot

Rick
sdo
Moderator
9 years ago
Once CBT has been configured for the VM, and then also effectively switched on by a stun/unstun event, then CBT will remain enabled.