Setting Up Changed Block Tracking

[huberw]

I am trying to replicate a VM from our primary site to a standby site. The VM has a single 30GB disk. The VM hardware version is Version 7. Both sides have ESX servers running ESX 4.0 Advanced (vStorage API is listed as one of the licensed features). The sites are connected via site to site VPN tunnel (20MB upstream FiOS on one side and 100MB ethernet to the internet on the other side).

I can successfully run replication jobs of this VM from one site to the other, WITHOUT changed block tracking (it processes the full size of the VM every time it runs). When enabling changed block tracking on the replication job, it allows me to do so, but when I run the job and look at the HTML realtime statistics it says the replication mode is "Network NBD WITHOUT changed block tracking."

Any ideas why? Is there something I need to do in ESX to make this work?

Thanks!

[Vitaliy S.]

Hello William,

No, you don't need to do anything additional to your ESX host to make it work.

Basically, for Change Block Tracking you only need ESX 4 or later host, and hardware version 7 VM.

You can always check if you have this line presented ctkEnabled (value = true), under VM Edit Settings -> Options -> Advanced -> Configuration Parameters. If it is present, CTK has been already enabled on this VM by Veeam Backup. And in this case, along with the line ctkEnabled = true, there should be other lines for the VMDKs as well. For ex : scsi0:0.ctkEnabled = true; scsi0:1.ctkEnables = true and so on.

Also please check if you have snapshots presented, because Change Block Tracking feature cannot be enabled if you have one or more snapshots present on VM. You will be able to create snapshots later, once Change Block Tracking has been enabled.

But can you tell me if you see any warnings during the job run? It'll be great if you could send us the logs from Help->Support Information to support@veeam.com, so we could see why change block tracking feature is not working for you.

Thank you

[Gostev]

Correct, everything is fully automated. Veeam Backup will either enable change tracking automatically for you, or will log warning in the session's log on why it could not do this (e.g. incorrect VM hardware version, snapshots present and so on).

[TrevorBell]

Hi do you mean something like this ??

4 of 8 files processed

Total VM size: 36.14 GB
Processed size: 2.40 GB
Processing rate: 14 MB/s
Backup mode: SAN/NBD without changed block tracking
Start time: 05/11/2009 14:56:37
Time remaining: 00:55:19

Backing up file "[CSVMW05_LOCAL] csflttest01/csflttest01_1-flat.vmdk"

Verifying changed block tracking...
Disk "Hard disk 1" has incorrect changed block tracking configuration.
Disk "Hard disk 2" has incorrect changed block tracking configuration.
Disk "Hard disk 3" has incorrect changed block tracking configuration.
One or more VM disks have incorrect changed block tracking configuration. To resolve this, open VMware vSphere Client, right-click the VM, choose Edit Settings, Options tab, select General, click Configuration Parameters, and set all entries with ‘ctkEnabled’ substring to false. Veeam Backup will then automatically re-enable changed block tracking with the correct settings during the next job run.

[Gostev]

Yes, this specific one is just more rare occurence. If I recall correctly, this one will appear if some disks were added/removed to VM after changed block tracking was first enabled, or something like this.

[TrevorBell]

i just followed the instructions in the notes and now all fixed

[mysticalice]

[merged]

I know this is a topic that's been covered over, and over, and over again, but before I contact support, i wanted to check with the forums to see if it's something you can suggest.

For some reason my ESXI virtual machines aren't getting backed up with changed block tracking. I've tried deleting ALL snapshots, and re-running the job, with the same issue. I get this:

"

3 of 5 files processed

Total VM size: 239.08 GB
Processed size: 18.00 GB
Processing rate: 16 MB/s
Backup mode: SAN/NBD without changed block tracking
Start time: 9/27/2011 7:55:01 PM
Time remaining: 03:55:23

Replicating object '[MVMLocal] HOUEXCHANGE/HOUEXCHANGE_1.vmdk'

"


VM hardware: 7, ESXI host version 4.1

Any idea why? I'm at a loss, and replications are taking half a day, when I know they should take a few minutes

[mysticalice]

This is not the same issue - can it please be unmerged?

[Vitaliy S.]

Basically there are no more special tricks to make CBT work, so to get a further assistance I suggest contacting our technical team. Also I would appreciate if you could update this topic with a resolution once you have it resolved.

[mysticalice]

I think that may be something I have to do - I'll give them a call/email tomorrow.

I'm a huge fan of VEEAM... huge. Of our entire backup strategy, VEEAM is at the top of the list in terms of software.