Restoring VMs from Differential Backup

[ETrosclair]

I am running Backup Exec 2010 R3 on one physical machine with VMware ESX 4.1 on a completely different physical machine. 

I've read through many how-tos concerning Differential Backups and most people say that all you have to do when restoring from these backup sets is restore the last Full Backup then the latest Differential and all should be good. Well obviously all is not good since I'm posting in the forum haha.

Here is the scenario I'm currently facing....

I have Full Backups stored in their own B2D folder on their own drive. I have each day's differential backup stored on its own B2D folder on its own drive. Backing up runs flawlessly for both Full and Differential jobs (I'm actually really impressed with the speeds I'm seeing).

Now here's where I get confused... 

I restore the Full Backup of this VM and it restores without issue. I can power it on and see that a lot of changes I made to this server have not been attached (which is where the differential will come into play). So my next step is to restore the differential. I power off the VM and set the job up to restore the differential set and after maybe 10 secs, I receive the following error....

The restore job cannot continue because the option to delete existing virtual machines prior to restore is not selected. Select this option on the restore job properties, and then run the job again.

So being the curious person that I am, I go ahead and select the option it tells me to select and have the job rerun. The restore completes successfully but upon trying to power on the VM, Windows will not boot up. I receive the "Operating System not found" message when I attempt to bring it back up. So to me, it's almost as if Backup Exec is not seeing the Differential Set for what it is.

So mainly my question has to do with the steps I'm taking and whether or not they are the right ones. If they are right in restoring from a differential then what would cause this situation to happen? Any advice would be greatly appreciated.

[NeerThadarai]

When you backup the Virtual Machine it has to be a part of the same Policy for the FULL and Differential to work properly.

While restoring a VM, there is no need to restore the FULL first and Differential next. Just select the Differential and restore it. That should take care of FULL restore of the VM and it should have the data till the last Differential.

[ETrosclair]

Could there be something wrong with the differential I'm restoring from? I tried restoring from just the latest differential I had and I would still get the "Operating System not found" message when it would try to boot. I'm recreating my entire test environment and will attempt to restore just from a differential once more and post results.

[Colin_Weaver]

Are you using SAN Transport for the restore or NBD? If Usimg SAN try the restore with NBD even if it was a SAN backup.

Also to clarify Neer's comments

An AVVI or Differential Restore, restores the differential or required incremetal (working backwards in time) first and then the full for you. Then the VMware Snapshot/Unsnapshot process re-assembles the different sets. Backup Exec as such maintains a links between the differential or incremental sets and the presvious full.

What interests me abouth your environment is that you have indicated that that Full and Incremental sets go to different B2D taget devcies can you try making the differential go to the same b2D as the full?

Also for info on AVVI Incremental and Differential Backups and restores please review

https://www-secure.symantec.com/connect/videos/backup-exec-2010-vmware-incremental-backup

https://www-secure.symantec.com/connect/videos/backup-exec-2010-vmware-restore

[ETrosclair]

Yes the Differential and Full backup jobs are a part of the same policy referencing the same Selection list.

No I am not using SAN transport. I am actually using NBD for backups and restores since that is the only transport that works in my environment.

When I first began testing with differentials, I had a setup where on a particular drive (Drive E for instance) there was a B2D folder for differentials and one for Full Backups. With this setup, everything worked great (backups and restores).

The only problem with that setup is that is not how my live backup strategy is planned out. Here's a quick rundown of my backup strategy....

• I currently have 7 individual full backup jobs that backup 7 individual VMs to their own B2D folder on a local drive. Once each job completes, each backup set is duplicated to its own B2D folder on a USB storage device for off-site storage. There are 10 of these devices that get changed nightly
   
• The setup I would like to have with differential jobs would be to have Full Backups of each VM run on Fridays that store to the local drive (in each their own B2D folder on the local drive that get overwritten weekly) then duplicate to the USB storage device (also with each their own B2D folder on the USB). I would have 2 of the 10 USB drives dedicated to Full Backups that would get rotated weekly.
   
• Differential jobs would run Monday through Thursday with basically the same setup as the Full Backups. Each VM would have its own B2D folder on the local drive (that would get overwritten nightly) as well as the USB storage device. I would rotate the remaining 8 USB storage devices nightly of course.

• I have the Differential policy already setup to do exactly what I want it to do concerning duplicating and what not so it is definitely not an issue with the policy since everything runs successfully.

So with all of that being said, I'm starting to wonder if Differential restores rely on having Full Backup sets on the same drive as the Differential sets. I am fixing to run a differential job as I type this out and will post the results of that restore.

[ETrosclair · Accepted solution]

I believe I may have answered my own question. After retrying, I noticed that the differential restore from the USB storage device failed when the FULL DUPLICATE on another USB device was not available.

Once I made the Full Duplicate available to Backup Exec, the differential restore ran without issue. 

I am somewhat bummed that a Duplicate Differential on USB couldn't use the Full Backup that was stored on the local drive but I do understand why it couldn't.

In the end, there must have been something wrong with my original test setup since all jobs were completing successfully.