Avamar VMware backup and container selection

I haven't played with VM containers but I think you need to select the parent folder in the left-hand pane, then select the folder you want to treat as a container in the right-hand pane. Give that a try.

perfect, it automatically discovered new VMs that were dropped into that folder after the fact.

Follow up question: This is a brand new Avamar installation, none of my VMs have CBT enabled. I have tested with a couple of VMs and it looks like as long as "Enable changed block tracking" is selected, CBT gets enabled for each VM/scsi disk automatically.  So i have read that to enable CBT you have to shutdown the VM or manually modify vmx file and then snapshot create/remove ? Is that what Avamar does automatically ..modifies vmx file and then creates/removes snapshot (which is really part of the regular VM image backup process).

Does it mean that first backup for a specific VM is not CBT enabled because it has not gone through this create/delete snapshot process ?

Thank you guys !

Ian, will probably need to expand this, but if CBT is not enabled at first then the changed blocks aren't being tracked within vCenter. Therefore, since Avamar is in play here, Avamar will only leverage it's technology and not the tight VMware integration Avamar has with VMware virtualized environments. Best practice is to enable CBT for all VMs. There are a couple use cases where it might not be appropriate, but it generally is.

Ed,

here is the thing, i took a VM that did not have CBT enabled, backed it up with Avamar. After the backup i looked at VM settings and CBT was enabled. So that tells me Avamar enabled that setting which is cool so i don't have to manually/script enable CBT on 900 VMs in my environment. I do would like to understand the specifics behind the scene what actually happened.

Ian Anderson wrote: If the appropriate GUI option is selected (and I believe it's selected by default in newer releases), Avamar will send an API call asking VMware to enable CBT for the VM. This change takes effect during a "stun-unstun" cycle which happens whenever a snapshot is created, removed or reverted. The stun-unstun also happens when a machine is powered on, resumed after suspend, or migrated.

Ian,

that's what i was suspecting, i saw a couple of blogs where people provided powercli scripts to enable CBT but that would still require manual stun/unstun ...but since Avamar is going to handle this for me life is beautiful

Hi Ed,

i was actually referring to this option here. So i am curious if dataset has CBT enabled and in the screenshot below you do NOT select "Enable changed block tracking" what would happen. To that ..why is it listed in both places (data set and when you define new VMware clients) ?

Thank you for your time.

If the appropriate GUI option is selected (and I believe it's selected by default in newer releases), Avamar will send an API call asking VMware to enable CBT for the VM. This change takes effect during a "stun-unstun" cycle which happens whenever a snapshot is created, removed or reverted. The stun-unstun also happens when a machine is powered on, resumed after suspend, or migrated.

The difference between the two settings is at what level you want CBT applied. If you want CBT applied to everything in your vSphere environment (your screenshot) regardless, then you might want to set CBT at that level.

However, if you want more granular control of where CBT is enabled, then you can leverage the dataset option (my screenshot).

I believe that information is recorded in the Avamar backup logs but we're straying outside my area of expertise.

If the change rate is in the 20% range or higher, the overhead from merging the changed blocks can be higher than the performance boost you get by not backing up the whole volume. For high change rate VMs, it's actually faster to back up the whole disk.

i am trying to think of use cases where it would make sense to not enable CBT ?  VMs that have high rate of change and seldom backups ?

Ian,

do you know of any assessment tools/scripts to determine that change rate ? We virtualize everything, from Apache/Jboss to Oracle/SQL.

Dynamox,

This is a very small use case where this condition actually occurs. The combination of Avamar with DD leveraging DDBOOST is one of the most choice ways to backup Oracle, or any database for that matter. Just be aware rare use cases that exist when using CBT.

-Ed