John Howard - Senior Program Manager in the Hyper-V team at Microsoft

Senior Program Manager, Hyper-V team, Windows Core Operating System Division.

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I'll zip that web server in 420MB - Small Virtual Machine Backups

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I've been meaning to try this for a while and finally got round to it at the weekend. Currently, on a monthly backup (or so - you know how things get in the way), I'll compact my Virtual Machine images running on my home domain, zip them up and burn them to DVD, and/or copy them to an external hard-drive for disaster recovery purposes. Obviously, each month this can be a bit tedious - the defrag/pre-compact/compact etc. - I may even get round to semi-automating this when I get some time. However, that's not what I'm writing about today.

One of my frustrations is that I've never been able to fit my six most critical VMs (IIS Web Server, Domain Controller, Exchange Server, WSUS (but not the 12 GB of data), Certificate Authority and ISA Firewall) on a single DVD. Until now that is. Of course, if you look back through my blog, you'll get the idea that each VM is running a fairly tight ship in terms of minimising what's physically on disk. However, I've been filling up around 7GB, or just under 2 DVDs each month so far just for VMs (plus another couple of DVDs for essential user data and other backups).

Yes, I could cheat and use a double-sided burner (which I do have, just not the DVDs themselves), but where would the fun lie in that? Instead, I turned to a utility I found out about maybe 15 or 18 months ago but never tried. Boy - I'm impressed with the end results. An example of some of the resulting ZIP sizes:

- Web Server: 420MB (Including logs but no data - it points at DFS shares hosted elsewhere)
- Certificate Authority: 520MB
- Exchange 2003 (With a lot of "family" data): 832MB
- ISA 2006 Firewall: 898MB (Including 12 months worth of log files)
- Domain Controller: 480MB

This was a saving of between 20 and 65% over last months backup. I've no idea why the huge difference in result - again for another days investigation. Each VM is running a full-blown Windows Server 2003 Enterprise Edition R2 OS. The answer to the figures lies in the choice of defragmentation utility prior to running the disk pre-compactor. Now please see my disclaimer - any utility operating at a disk level can cause loss of data, this utility is not a Microsoft supported or endorsed product, and your mileage may vary. Also, it's worth turning off all un-necessary services before running defragmentation (in my experience, that is). With that said, check out here.

By the way - all my VMs have a seperate fixed disk to hold the swap file. I don't back these up - if you can't get figures close to these, that may be another thing to consider as well as looking back through my blog for other tips.

Cheers,
John.

Comments
  • Microsoft blogger John Howard got me thinking with his post "Small Virtual Machine Backups". In his post,...

  • I apologise in advance - this is probably the *WORST* bit of scripting I have ever written. However,

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