A couple of VCB/SQL/Exchange questions

[FunkyD]

I have ESX 3.5 U2 and have configured VCB on my BackupExec 12 server. A file based backup works fine on my test Vmachine.

I am now at the stage where I can start to use VCB on my production servers.

My first question refers to using VCB on a SQL 2005 server. Normal practice would be that you would stop the SQL services as part of a freeze script, VCB and then start SQL services as part of a thaw script. I could use this but I am running Database Mirroring. If I stop SQL server then the other server will think there is a problem, alarms will go off and all sorts of problems and emails flying around. The real problem is the server apps - if they can't connect because SQL is down they will try to redirect to the backup server.

So, can I backup just the C drive (Databases and logs are on F and L drives) without shutting down the server? If it is possible to snapshot just the C drive will that affect SQL at all? I could then restore the server, add some hard drives manually and recover SQL data from another backup mechanism?

With Exchange, can I do the same thing? I am running SCR on my Exchange server so wouldn't want to risk that going wrong either.

VCB seems to be a very good tool but the fact that there is a chance any system that runs a database might either fail while being backed up or the actual backup be inconsistent is a PITA!

Thanks

[admin]

Starting with ESX 3.5 Update 2, VCB and ESX takes advantage of Microsoft VSS when taking snapshots on Windows machines. You need to make sure you have upgraded the VMware Tools and the VSS option is enabled in Tools. Are you using the BE SQL agent at all? This is important as the VMware snapshot takes a VSS COPY backup that does not truncate logs. You will need some other mechanism for log maintenance.

Thanks,

Paul

[FunkyD]

Hi,

Thanks for the reply . Are you saying that VCB, when used on a SQL server, actually makes a copy of databases? How does this work? I'm not sure I fully understand what you are saying. ?:|

I am not using the SQL agent for BE as I schedule backup jobs to disk in SQL directly so that takes care of my logs.

In summary, are you saying that the issues with the SYNC driver are no more because VSS is being used? I can use VCB on servers running databases without fear of anything unexpected happening? Some people had problems with Exchange or MS SQL or Oracle under heavy load that either mean't the backup data was corrupt or data lost on the virtual machine itself.

Thanks

[admin]

Yes and no. VCB does not make copy of the database directly. When VCB requests a snapshot, the snapshot is taken with VSS and the snapshot is your copy, but a copy of the entire VM, including a quiesced database. There are various types of VSS snapshots or backups. The VMware VSS implementation uses VSS_BT_COPY.

http://msdn.microsoft.com/en-us/library/aa384679(VS.85).aspx

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VSS_BT_COPY

Files on disk will be copied to a backup medium regardless of the state of each file's backup history, and the backup history will not be updated. (My comments - we do not actually copy anything to backup medium)

A requester can implement this sort of backup on a particular writer only if it supports the VSS_BS_COPY schema.

If a requester's backup type is VSS_BT_COPY and a particular writer's backup schema does not support that sort of backup, the requester will always perform a full (VSS_BT_FULL) backup on that writer's data.

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If using VCB solely, you would want to run another backup that truncates logs, or some other method like you are doing in SQL itself. And yes, the VSS implementation should take care of all sync driver issues since the sync driver is not application aware like VSS. Unless there are issues with the VSS framework in the VM, you will end up with a consistent database and VM. This would also apply to all VSS aware applications such as Exchange, AD etc.

[AndreTheGiant]

Are you saying that VCB, when used on a SQL server, actually makes a copy of databases?

You can do it using guest script that can be execute by VCB pre and post snapshot.

Andre

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