Time Machine and Virtualisation

[ICEBreaker]

Dear forum members,

Does Time Machine work with files that reside within the virtualised partition? I am guessing yes and no.

Yes - it backs up the virtual file and so you can return to a prior state.
No - it is at the virtualisation file level and not on a file level, so it is impossible to preview and bring back just one file.

If it backs up the entire virtual file, wouldn't time machine run out of space very quickly, since the whole file would be back up every time, as opposed to just backing up the parts that changed.

Thanks!

 

[Queso]

I'm guessing that Time Machine is most likely going to work on the same technology as Snapshots from Network Appliance, in which case it will take a baseline backup of a file then a collection of "deltas" (meaning the changes) which when applied to the baseline file one by one result in the current file version. To restore any version of the file, you just need the original baseline plus all the deltas up to the date you're requesting from, which is how Time Machine can keep so many different file versions on the same disk without running out of space. If this is correct, your virtual machines aren't going to take up much space unless you're doing major changes within them every time you activate.

Not too sure whether you can back up files from within the virtual hosts themselves though.

 

[ICEBreaker]

Dynamicv, thanks! I do hope it can really just store the file's delta, rather than store any files that have changed. I suppose I should store the data files on the Mac's filesystem itself, rather than within the virtualised filesystem, to avoid data loss due to corruption, and to expose it to Time Machine.