How Does SD Work With Virtualization?

[nucleotide]

Hi, new to mac. I'm planning to hook an external HD (Samsung F3) onto an iMac (SnowLeopard) and trying to decide on my backup options. Thinking of installing Parallels 5, and have read on here that SD does indeed backup Parallels.

What I don't quite get is if Parallels contains Windows files (presumably NTFS), how is SD (which runs on HFS+) able to save Parallels? Does Parallels somehow convert Windows files to FAT32 ?

Also, I understand there are problems with Time Machine treating virtual machines as one large file. How does SD handle saving virtualization folders differently?

Thanks.

[dnanian]

Most standard installations create a 'disk image' hosted on your HFS+ volume. Inside that image is a virtual Windows disk, and that's what's backed up.

Parallels/VMWare/etc should not be running when you back up.

TM is a problem because these images tend to be very large, and backing them up each time would result in a lot of disk space being used. Since SD! doesn't keep multiple versions, it's not a problem.

[nucleotide]

Originally Posted by dnanian

Most standard installations create a 'disk image' hosted on your HFS+ volume. Inside that image is a virtual Windows disk, and that's what's backed up.

Parallels/VMWare/etc should not be running when you back up.

TM is a problem because these images tend to be very large, and backing them up each time would result in a lot of disk space being used. Since SD! doesn't keep multiple versions, it's not a problem.

Thanks. So the disk 'image' does not affect the file system itself then?
And SD still backs up the entire image, it just doesn't keep each new version and simply overwrites the previous version?

[dnanian]

I don't know what you mean by "the disk 'image' does not affect the file system itself then"...

And, yes - SD! backs up the segments of the image that have changed (if it's a sparse bundle-like image), or the entire image file (if it's one big file).

[nucleotide]

Originally Posted by dnanian

I don't know what you mean by "the disk 'image' does not affect the file system itself then"...

I asked how SD manages to save the virutalization folder if SD is on a different file format/system (e.g. HFS+) than the virtual Windows disk (presumably NTFS ?). I thought this would be incompatible...?

[dnanian]

You're not saving a 'virtualization folder'... you're saving the disk image file along with the other files on your HFS+ volume.

[nucleotide]

Originally Posted by dnanian

You're not saving a 'virtualization folder'... you're saving the disk image file along with the other files on your HFS+ volume.

Ok. What file system/format does the disk image use?

[dnanian]

I have no idea: it's whatever Parallels or VMWare, etc, use.

[Dewdman42]

I am just pondering the best way to approach backing up my mac, which has a frequently used Parallels XP instance on it. Trying to figure out the best way to avoid copying a bunch of stuff redundantly. Sounds like its pretty much a no brainer that Parallels should be stopped when SuperDuper runs. Unfortunately, the disk image size of parallels can often still be quite a bit larger then neccessary as well unless you run the Parallels compress command ahead of time, etc.

I'm kind of thinking the right approach is to keep as much of my critical windows data OUTSIDE of the VM where it will get backed up by SuperDuper nightly. Then have SD ignore the parallels image and just keep one copy of that image file somewhere else in case I need to restore it. Of course as I change the windows config, it has to be backed up too. Dunno...

It adds 50% or more to the size of my SD backup if I leave the parallels image included in the SD backup too, and I have to remember to shut down parallels before I got to bed.

[dnanian]

Well... I'd still remember to shut down Parallels and take the size hit. It's much easier to restore that way.

[hassiman]

Just do a normal SD backup and as stated make sure your VM is shut down before backing it up. You will BU all your files including the data that is contained in your Windows VM.