Re: [BackupPC-users] Backup of VM images

Les Mikesell <lesmikesell AT gmail DOT com> wrote on 06/07/2011 11:42:56 AM: > On 6/7/2011 9:51 AM, Boniforti Flavio wrote: > > Hello Jim > > > > [cut] > > > >> Were I attempting to back up the images I would assume that > >> the unused areas would be included. My solution to backing up > >> my VMs was to install backuppc for each of them and treat > >> them the same as physical machines on my net. This did lead > >> to problems backing up Win2K and WinXP VMs, but only those > >> already fully addressed for physical systems. > > > > I understand you are/were working on the same LAN. > > > > My trouble begins at the point where there are 15km between the HQ and > > the backup location! > > That's a problem that a sufficient amount of money can solve, with > 'sufficient' varying wildly depending on your location and network > providers. But in any case it is likely to be more efficient to back > up the live machines (virtual or otherwise) than their disk images - and > that way you also get useful pooling for the storage.

I strongly recommend both: BackupPC to back up inside of the virtual machines, and some sort of regular (say, monthly or weekly) snapshot backup of the entire VM image.

Trying to restore a single file from a snapshotted VM is a *lot* harder than using BackupPC to do it. But using BackupPC to try to restore a crashed VM is a *lot* harder than using a snapshot backup (and then using BackupPC to make sure the files are up to date).

> One other point that I'm not sure anyone mentioned yet is that the rsync > comparison is normally against the previous full run, so it will be > important to either do only fulls or set incremental levels to make each > run backed by the previous so the differences don't accumulate over time.

I'm not sure that really matters. The bandwidth usage will be similar to the difference between incrementals and fulls in a traditional BackupPC setup (i.e. you already have those same bandwidth issues: the VM's aren't going to make it worse). The biggest problem is that *every* backup is going to have to read 100% of the data every time. In other words, there really is no such thing as an incremental: an incremental and a full will read the same amount of data on both ends.

You could certainly use BackupPC for backing up VM's: it's just a matter of scale. But having an aged series of snapshot backups makes *very* little sense. You will *NOT* want to use your snapshot backups to try to pull back old files. You really just want a handful of very recent copies (in case one is bad or you make some sort of catastrophic change you want to back out). Your aged series of backups should be done at the file level (inside of the VM), and that's 100% a standard BackupPC solution.

Timothy J. Massey


Out of the Box Solutions, Inc. Creative IT Solutions Made Simple! http://www.OutOfTheBoxSolutions.com tmassey AT obscorp DOT com		22108 Harper Ave. St. Clair Shores, MI 48080 Office: (800)750-4OBS (4627) Cell: (586)945-8796

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