VM with very high change rate - Disable CBT?

[bgalante]

Hi,

I have a VM with a 1TB volume, and its about 700GB full. The volume contains "Dragon profiles". (Speech translator software's user profiles).
The way I understand it is these profiles are copied to/from users local machines to the server back and fourth depending on what profile is newer.
I'm getting a minimum of 200GB data transfer on my daily incremental backups sometimes as high as 300-400GB, but I dont believe there is that much data changing.
I believe that because it is re-written / copied this is triggering Veeam to detect a higher rate of change when perhaps it is not.

I was thinking that disabling CBT in the backup job might be worth a try, wondering if anyone has any input of this type of situation..

[DaveWatkins]

With CBT disabled Veeam will read the whole disk for each backup. It may shrink the backup file sizes but that'll be offset with the time and IOPs of fully reading the disks, as well as the overhead to compare hashes for every file. It might be worth it in your case though

[skrause]

You have to remember that Veeam backs up VMs at a block level. Veeam will still be doing its own checking of changed blocks through their filtering mechanism even if you turn off using the hypervisor's CBT. Any change to a file (that isn't excluded) is going to cause that block to be backed up, regardless of your CBT settings.

I would check with the Dragon software vendor and see if they have any options that would cut down on the amount of disk churn.

[kubimike]

lol at calling dragon for anything, worst support ever.