Resetting CBT / Necessary if running active full?

[Doug.Butler]

In a recent episode of Gostev's "Veeam Community Forums Digest" it was strongly stressed to patch VB&R and reset CBT for all protected VM's due to some sort of a known issue that could corrupt backup data.

Just last night I did install V7 Patch 4 (cumulative patch) while working with tech support on a different issue.

My question is now about the necessity (or not) of manually resetting CBT for each VM. If I have to reset CBT for all VM's this will be a cumbersome process as I am currently dealing with a lack of space on the repository. If I do them all at once, then I will run out of space because I will have multiple full backups for each VM.

BUT, the reason for the lack of space right now is that I have a policy setting to do an Active Full backup once a month, and as a result I currently have two full .vbk files on the repository anyway. (For as long as my policy requires me to retain VM backups that are part of the 'older' .vbk backup chain.)

So the basic question is: Will the Active Full backup automatically reset CBT for me anyway? Or do I still have to do it manually for each VM?

[Gostev]

Resetting CBT does not cause full backup, so there is no impact on the repository disk space.

Active Full backup does not reset CBT, so you do need to do it manually. However, just resetting CBT is not enough, you should also install a patch from KB1940 to prevent future corruptions.

[Doug.Butler]

Doesn't cumulative patch 4 include the CBT fix (KB1940)?

Won't resetting CBT on an individual VM mean that the next backup of that particular VM is, in effect, a full backup? If so, then won't resetting CBT for ALL VM's (or a large number of them) effectively mean more disk space for that backup run?

[Gostev]

No, as Patch #4 was released months before the CBT issue even became known.

No, resetting CBT does not make the next backup of a VM a full backup.
The job will still do an incremental backup, just without using CBT data.

[Doug.Butler]

Ok good to know that I need to do the separate patch. I was very unclear on that - I thought the patch was in the cumulative update.

Still don't quite understand how the job can do an incremental WITHOUT CBT - but if you say it does, I'm happy with that.

Thank you!

[foggy]

Still don't quite understand how the job can do an incremental WITHOUT CBT - but if you say it does, I'm happy with that.

Veeam B&R will use its proprietary change tracking algorithm that requires reading of the entire VM disks to calculate blocks that should be transferred.

[Doug.Butler]

Thanks. Hey I know this is the wrong context (forum) to give this feedback, but in looking at the KB1940 instructions, there is an error (at least there was for me) in the instructions for how to apply the Hotfix.

It says to put the DLL's in a folder that doesn't exist.

It says: "3. Replace DLL's in C:\Program Files\Veeam\Backup and Replication\Backup with DLLs from the hotfix package"

But there is no "Backup" subfolder, so the DLL's just go in C:\Program Files\Veeam\Backup and Replication\

Easy to figure out, but figured you'd want the instructions to be letter-perfect.

Also I did go through the rest of the instructions in the KB and used the scripts on my hosts to reset CBT on most of my VM's last night. In the process I found a few orphaned snapshots that I deleted manually, but the script seems to have been a success. I still have a few VM's to do but wanted to see the results of overnight backup job first.

Thanks

[foggy]

Doug, there's actually the Backup folder and DLL's should go right in this very folder, not into the parent one.

[Doug.Butler]

Not on my server, there isn't.

Can't paste screenshots here, but I ran a DIR command to search for the DLL's in the hotfix; I'll paste those results here.

Code: Select all

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

Z:\>c:

C:\>dir Veeam.Backup.AgentProvider.dll /s
 Volume in drive C has no label.
 Volume Serial Number is 0AFD-4B7D

 Directory of C:\Installers\Veeam\Veeam Backup & Replication\v7\CBT Hotfix\cbt_h
otfix_7.0patch4

12/03/2014  08:39 PM           222,720 Veeam.Backup.AgentProvider.dll
               1 File(s)        222,720 bytes

 Directory of C:\Program Files\Veeam\Backup and Replication

12/03/2014  08:39 PM           222,720 Veeam.Backup.AgentProvider.dll
               1 File(s)        222,720 bytes

 Directory of C:\Program Files\Veeam\Backup Catalog

08/13/2013  08:10 PM           214,528 Veeam.Backup.AgentProvider.dll
               1 File(s)        214,528 bytes

     Total Files Listed:
               3 File(s)        659,968 bytes
               0 Dir(s)  61,744,340,992 bytes free

C:\>

And also, here's a DIR /AD command on the Backup and Replication folder, showing the subfolders only, and there is no "Backup" subfolder.

Code: Select all

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

Z:\>c:

C:\>cd "Program Files\Veeam\Backup and Replication"

C:\Program Files\Veeam\Backup and Replication>dir /ad
 Volume in drive C has no label.
 Volume Serial Number is 0AFD-4B7D

 Directory of C:\Program Files\Veeam\Backup and Replication

12/03/2014  08:46 PM    <DIR>          .
12/03/2014  08:46 PM    <DIR>          ..
12/04/2013  05:24 PM    <DIR>          Controls
12/02/2014  06:28 PM    <DIR>          DashBoard.61
12/02/2014  06:28 PM    <DIR>          ExchangeExplorer
12/04/2013  05:24 PM    <DIR>          Images
12/02/2014  06:28 PM    <DIR>          LiveCD
12/04/2013  05:24 PM    <DIR>          MksConsole
12/02/2014  06:28 PM    <DIR>          Packages
12/02/2014  06:28 PM    <DIR>          Putty
12/04/2013  05:24 PM    <DIR>          SbRoles
12/02/2014  06:28 PM    <DIR>          SharePointExplorer
12/02/2014  06:35 PM    <DIR>          Upload
12/04/2013  05:24 PM    <DIR>          vddk
12/02/2014  06:28 PM    <DIR>          VSS
               0 File(s)              0 bytes
              15 Dir(s)  61,726,244,864 bytes free

C:\Program Files\Veeam\Backup and Replication>

[Gostev]

What about

Code: Select all

C:\Program Files (x86)\Veeam\Backup and Replication

[foggy]

Any chance Veeam B&R is installed in some alternative location (not the default one)?

[Doug.Butler]

What about

Code: Select all

C:\Program Files (x86)\Veeam\Backup and Replication

I can check, but I know the DLL's aren't in that location (even if it exists) because when I determined the "backup" subfolder didn't exist, I went to the root of the volume and searched the entire volume for those DLL's.

See my earlier post for the search for Veeam.Backup.AgentProvider.dll - you can see the folders that contained a file by that name.

[Doug.Butler]

Any chance Veeam B&R is installed in some alternative location (not the default one)?

Nope, I rarely (virtually NEVER) change anything from the defaults when I install stuff. And I know I didn't change this install.

See my last post as well. When I saw the discrepancy in the instructions, I went to the root of the volume and used DIR to find every DLL with the same name as one of the ones in the Hotfix package.

[kte]

do we need to replace the original dll or not ?
Wbecause the backup folder did 't exist on 1 of our backup servers

[foggy]

Nope, I rarely (virtually NEVER) change anything from the defaults when I install stuff. And I know I didn't change this install.

Was it probably upgraded from pre-v7 then? I remember we did install the product directly into the C:\Program Files\Veeam\Backup and Replication folder previously.

[foggy]

do we need to replace the original dll or not ?

Yes, you need to replace the original DLL files in your installation.

[Doug.Butler]

Was it probably upgraded from pre-v7 then? I remember we did install the product directly into the C:\Program Files\Veeam\Backup and Replication folder previously.

Yes. I did an in-place upgrade from version 6.

[foggy]

That explains. We should update the KB to reflect that the folder differs for upgraded backups servers.

[Doug.Butler]

That explains. We should update the KB to reflect that the folder differs for upgraded backups servers.

Sounds good. I'm glad I reported it.

Thanks

[meggerz]

So just looking for some clarification. Is it best practice to run a full backup after disabling or enabling CBT on a VM?

[foggy]

Hi Megan, active full is not required, unless CBT reset was done to recover from some sort of corruption and you suspect that your previous backups might not be good.