VCB Concepts - am I on the right track?

[sammyc53]

Ok, I am trying to decipher the VCB Manual right now. I am wanting to make sure I am correctly grasping the concepts and sequences of events that occur during a VCB Backup that utilize Custom Quiescing Scripts.

Let me see if I have this right:

Example VM: Exchange 2003

vcbmounter.exe is called

Pre-Backup Script is invoked

Runs a pre-freeze script in the VM, C:\Windows\pre-freeze-script.bat (Custom Quiescing Script)

Shuts down the Information Store, allowing a quiesced snapshot of the Database

Engages SYNC driver to do it's magic, flushing I/O and dirty data, making file system consistent.

Quiesces NTFS, ensures that no file system writes are pending at the time the snapshot is taken, allowing the creation of file-system consistent backups

Snapshot is created

Unquiesces NTFS

Disengage SYNC drivers

Runs a post-thaw script in the VM, C:\Windows\post-thaw-script.bat (Custom Quiescing Script)

Starts Information Store

Exports the virtual machine snapshot, disks, and configuration files to a local directory on the VCB proxy

Snapshots are unmounted

Backup software graps the files that VCB exported.

End result: An image-level backup that are file AND database consistent, as apposed to being crash-consistent, correct?

Question: SYNC seems to be optional, does it have to be enabled in this senario?

[BUGCHK]

The SYNC driver will not help with a consistent Exchange backup - if you are unlucky, you will backup a 'set of files'/ a database that is not even crash-consistent:

http://kb.vmware.com/kb/5962168

VMKB5962168 - Microsoft Exchange Server on a Virtual Machine Can Freeze Under Load When You Take Quiesced Snapshots or Use Custom Quiescing Scripts

If you look through the forums you might find some older articles about this topic.

A recent ESX environment includes a VSS provider, but I don't have any experience with that.

[dconvery]

Actually, your idea may work. If you use the pre-freeze to stop all exchange services and the post thaw to restart them. The only thing that makes me nervouse is the amount of time it takes to copy the vmdk files to the holding tank. During that time, the snapshot is filling up with data. At the end of the file copy, the snapshot is committed and deleted. If it is a large mail store, this could take a fairly long time. VCB uses CMD.exe for all of its processes, CMD.exe limits SAN copies to a little less that 1GB per minute.

I always recommend using a proven backup agent for Exchange. If you do not want that expense, just use NT Backup and send the backup file to a network file server that is backed up.

Dave

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Accomplishing the impossible means only that the boss will add it to your regular duties.

Doug Larson

[sammyc53]

...VCB uses CMD.exe for all of its processes, CMD.exe limits SAN copies to a little less that 1GB per minute.

I always recommend using a proven backup agent for Exchange. If you do not want that expense, just use NT Backup and send the backup file to a network file server that is backed up. ..

Yeah, I was kinda worried about this too, but how do other software packages manage to get around this? Or do they? There are many 3-Party products that tie into VCB, wouldn't they be subject to this too?

Not even sure it will really be that big of a deal. I might just do this process on a monthly basis, in addition to my existing backup agent for exchange.

[dconvery · Accepted solution]

What I usually recommend for customers is this:

Make your drives C:, D:, E: All drives for logs and data can be on RDMs. If RDMs, do not make them virtual mode.

Install Exchange on C: and point data, logs, etc to the other drives.

Do a weekly selective fullVM backup of C: only. Take a look at this method ->http://communities.vmware.com/blogs/jturver

Use your backup software client to back up C:, system state and Exchange. (I recommend at least the mailstore. Add "brick-level" if there is enough time)

Restore will be this:

Use VMware COnverter to create the Exchange VM from the VCB backup. You will need to manually create the data drives.

Use backup software to restore the exchange. You MAY need to restore C: and System State (again) from the backup client as well.

MAKE SURE YOU TEST AND DOCUMENT THE RECOVERY PROCEDURE!

Dave

************************

Accomplishing the impossible means only that the boss will add it to your regular duties.

Doug Larson

[sammyc53]

Dave! This excact process just started brewing in my head!

That is basically is how I have my box set up, C/D/E: etc... (Except I don't know what a RDM is...) And I do daily Fulls.

Thanks for the tip!

[beagle_jbl]

VCB integration with 3rd party backup software is pretty weak so far. Netbackup is probably the furthest along (you can do image level backups with deduplication, and still do file-level restores from the image level backup which is sweet).

As of today, I don't know of anyone doing application specific backups using VCB. It has to be coming - one would think - but for now I think everyone is using traditional backup agents within their VM, and backing up he application over the network or to another partition (RDM or VMDK).

[sammyc53]

BackupExec 12.5 integrates with VCB very well - however I can't afford the additional license it will take to enable it

[dconvery]

Some add'l info for you:

I did a session at VMworld about VCB with NetBackup. A companion doc is here ->http://viops.vmware.com/home/docs/DOC-1133

It explains the setup of VCB and the concepts for pre and post are the same. While you are at VIOPS, check out the docs under availability. CHris Skinner probably did a doc for BE12.5

Also check out this. It is a little dated, but may help. ->http://communities.vmware.com/docs/DOC-2770

Dave

************************

Accomplishing the impossible means only that the boss will add it to your regular duties.

Doug Larson