VMware Fusion large source files

April 14, 2008 / Filed under: VMware, Storage, Rants

I've been using VMware Fusion on OS X whenever I need to run Windows XP. It is great to have both environments running side-by-side.

One issue I've noticed with VMware is the very large source files. A "virtual machine" is simply a document on your hard drive. I leave my Windows XP virtual machine on my OS X hard drive, and launch it whenever I need XP.

Screenshot of OS X Finder

Notice the file size in the image above: 13.77 GB. This size increases whenever I add new things to my XP installation - new programs, etc.

Problem is - it's very hard to backup this file. I've been learning a lot about hard drive formatting (FAT32), as I scour the web for answers on how to backup my VM file.

It simply won't copy to any devices/locations I've tried:

  • USB external 120 GB hard drive
  • Network drives
  • External web storage sites

I've even zipped the file, which cut the size down to 7.5 GB. Still too large to copy or upload anywhere. It's basically stuck on my machine, primed to be lost if my laptop gets stolen or damaged.

What are my other options?

Future-proof resolution

It turns out, after consulting with a VMware Fusion rep, there is a new feature available in the latest version of Fusion, which allows you to split a VM into 2 GB chunks.

Some file systems, such as FAT and UFS, are unable to support very large files. If you are creating a virtual machine that will be used in a hard drive with a file system that does not support very large files, select the New Virtual Machine Assistant option Split disk into 2GB files. This option is in Advanced disk options, in the Virtual Hard Disk panel of the New Virtual Machine Assistant.

This is great, but it only seems to work for new VM installations. It does no good for my existing VM.

Comments/Mentions

# BiL castine at 4/16/2008 9:24 pm cst

i regularly copy 15GB Parallels VM disks between several locations. i copy them to/from a windows server, though the standard SFM piece of Crap MS calls "Mac Compatible" is only compatible with OS 9's AFP which is limited to <2GB files and 32 character filenames, so i use the most excellent (and frightfully expensive) ExtremeZ-IP to provide modern AFP services. you could also format your external drive (USB, FIreWire, Keychain, etc...) as HFS+ which would allow >2GB files. lastly, you could use DropStuff to split the compressed image into segments <2GB to allow them to be stored on FAT32 formatted media.

hope this helps.

# Peter Kazanjy at 4/17/2008 4:00 pm cst

Matt:

Here's a way to take your current "monolithic" disk, and make it into a split disk. Hope this helps!

~Pete VMware Fusion Product Marketing

NOTE: Make sure to power off/shut down the VM before doing the below things.

1) Download vdiskmanager GUI from the VMware Fusion user forums, vmware.com/go/fusionforums

2) Click on the Convert tab

3) Click on the Input button, select the source monolithic disk

4) Check the "Split disk into 2 GB files"

5) Click on the Output button

6) Save the virtual disk as the same name as the source monolithic disk, but save in a different folder

7) Once converted, move the monolithic disk to a new folder

8) Move all the contents of the split disk to the original VM bundle

9) Power on the VM

10) Assuming the VM powers on and boots correctly, you can now throw away the original monolithic disk

# Mark Wheadon at 6/30/2009 6:36 am cst

You can improve matters by storing your VM(s) in a sparse-bundle filesystem:

http://www.markwheadon.com/blog/2009/06/backing-up-virtual-machine-using-sparse-bundle/

That way, the data is split over much smaller files and so the incremental backups are smaller.

Cheers,

Mark