Parallels increases time machine backup size... ALOT?

Discussion in 'Mac Apps and Mac App Store' started by el-John-o, Jan 8, 2013.

  1. el-John-o macrumors 65816

    Nov 29, 2010
    I know this is sort of a 'known' issue that Parallels causes an unusual increase in backup size. What I mean is, if I don't use Parallels in between backups, I'll get a quick backup of a couple hundred megs. If I DO use parallels, my backup might be 40 or 50 GIGS!

    So, the solution I read everywhere is to not backup parallels with Time Machine. Well, okay, I guess. Not the end of the world. But IS there a better way? Is there a way to reduce the size (anyone know WHY Parallels does this) or otherwise?

    One of the allures of Time Machine is that I can be back to the way I was before, exactly, in the event of a Hard Disk failure. I'd like to do that, without having to re-install Parallels, Windows, Office, etc.


  2. Nermal Moderator


    Staff Member

    Dec 7, 2002
    New Zealand
    The reason that it happens is because Parallels has a single file containing your Windows virtual hard drive. As soon as you change anything in Windows, then by necessity that file has changed and Time Machine will therefore back it up again.

    As for working around it, I'm not sure of any "elegant" way. VMware (and presumably Parallels) lets you use a separate partition for Windows, and therefore OS X will see and be able to back up individual files. The disadvantage is that you need to predict your space requirements and pre-allocate the partition space.
  3. justperry macrumors G3


    Aug 10, 2007
    In the core of a black hole.
    That's why I think a better way is to use CCC and using scheduled backups, for instance, once every hour for your home folder without parallels and once a day or weekly to backup the whole disk.
    There are plenty of options in Carbon Copy Cloner, another good thing about it is it is bootable.

    CCC is free up to version 3.4.6
  4. el-John-o thread starter macrumors 65816

    Nov 29, 2010
    I figured it had to do with the VHD.

    Seperate partition is a no go, as I just hate dealing with partitions. I just need to decide if it's worth backing up at the cost of a ton of space on my Time Capsule (thus less backups stored at any time), and of course the time it takes to backup (though that's not much of an issue, it's not like you have to do anything, or that it slows you down or anything).

    Hmmm... decisions decisions...
  5. Mr. Retrofire macrumors 603

    Mr. Retrofire

    Mar 2, 2010
    Time Machine does it. The solution is:
    1. Create a new folder and call it “VMs”.
    2. Shutdown all VMs and move them to the new “VMs” folder.
    3. Tell TM, that it should not backup this “VMs” folder.
    4. Create a manual backup of this “VMs” folder every week, or if necessary.
  6. James Craner macrumors 68000

    James Craner

    Sep 13, 2002
    Bristol, UK
    Parallels Desktop for Mac now has improved integration with Time Machine.

    When backing up the virtual machine, it will only backup the recent changes (the latest snapshot), but not the whole virtual hard drive. Thus, the backup process will take less time and use less space on your Time Machine storage device.

    To enable improved integration with Time Machine, go to Virtual Machine Configuration, choose Options and hit Backup.

    Select "Optimize for Time Machine" in SmartGuard menu.

    If you do not want your virtual machine to be backed up by Time Machine, you need go to Virtual Machine Configuration --> Options --> Backup and put a checkmark on “Do not back up with Time Machine”.
  7. maflynn Moderator


    Staff Member

    May 3, 2009
    That's because TM sees the parallel's VM as a single file object and backs the entire container object up when ever it notices a difference. So if you have a 40 gig VM, it will back that up continually as you use parallels.

    I exclude my VMware virtual machine from Time Machine and manually copy it to my NAS. That keeps my backups small but I have a backup of my virtual machine
  8. hallux macrumors 68030


    Apr 25, 2012
    What I do is use a TrueCrypt volume for the data that's shared between my Oracle VB VM and OS X (I only use my VM for Quicken so my TC volume is my financial stuff). I then use VB Add-ons to mount the TC volume in my VM. I exclude the VM from TM backups, but the TC volume IS backed up.

    I'm not sure if Parallels has the same capability but this works well for me. I don't care about losing the VM, everything in it can be "recovered" by creating the new VM and reinstalling the OS in it.
  9. el-John-o, Jan 8, 2013
    Last edited: Jan 9, 2013

    el-John-o thread starter macrumors 65816

    Nov 29, 2010
    Thanks guys

    As I mentioned, I am aware I can disabled backups for Parallels, I just wanted to avoid that because I don't want to re-install it in the even of hardware failure.

    I am going to try that 'optimize for time machine' option and see how that works out. Thanks!


    Just in case anyone searches and stumbles on this thread, the suggestion from James Craner about the little hiding 'optimize for Time Machine' setting worked like a charm. Backups are still a smidge larger if Parallels is running or has run (even if I haven't actually DONE anything in parallels), to the degree of perhaps an 800mb backup instead of a 250mb backup, but that is substantially better than a nearly 50 GIGABYTE backup.

    Works great, now I can conserve space on my time capsule whilst retaining a full and complete backup so if anything ever happens, I can be right back where I was!
  10. macpeterr macrumors newbie

    Jun 24, 2008
    Maybe this can help you out. I wrote an article how to backup Parallels VMs using rsync. I have multiple VMs (approx. 400GB in total) for which i keep an backup. Using rsync my backup time for VMs is now only a fraction of what is was before.

    "Backing up Virtual Machines (or other large files) on OS X"

  11. el-John-o thread starter macrumors 65816

    Nov 29, 2010

    I skimmed the article (will sit down and read it this evening). However it appears that this is another manual backup solution right? I mean I could do something to make it operate automatically but it's still separate from time machine right? If that's the case, using Parallels built in snapshot feature seems like a better solution, as it centralizes my backups on my time capsule (with all important files being on my NAS and subsequently backed up to the cloud)
  12. phrehdd macrumors 68040


    Oct 25, 2008
    1)Skip the Parallels " Windows file" from the Mac back up.

    2)Create a share folder between Mac and Parallel Windows. Store all your Windows created data in that share folder and let it be backed up along with Mac.

    3)Back up the Parallel Windows file ONCE. Only consider backing it up again if there is a change such as an update or you added or removed software.

    That is pretty much one of the simplest ways to handle this.

    In short, your files created in Parallels gets backed up along with the rest of your Mac (Time Machine etc.) The Parallels virtual Windows is only backed up once and then again if changes occur to the virtual Windows such as updates and added software.
  13. flynz4 macrumors 68040

    Aug 9, 2009
    Portland, OR
    This is what I do. My VM is "data-free". All of my data is in shared folders with OSX... and hence get backed up with OSX backups.

  14. macpeterr macrumors newbie

    Jun 24, 2008

    You can automate it using crontab (commandline) or calendar in combination with automator, etc. On the commandline enter crontab -e, this will open a vi editor. Add a line (details here; for example "00 08 * * * /Applications/Syncfolders/syncfolders.command" and close the editor with <ESC>wq. This will schedule the script to run every day at 08:00AM.

    If you want to ben notified when a backup completes download the latest version of terminal-notifier ( and install it in your Applications folder and change the syncfolder function in the script to;

    function syncfolder {
     targetfolder=`echo $targetdir | sed "s#^.*\/\(.*\)#\1#"`
    echo Start RSync from "${sourcedir}"
    /usr/bin/rsync --archive --hard-links --one-file-system --compress --progress --exclude-from=syncfolders.exclude --log-file=${sourcedir}/rsync.log --rsync-path="/usr/bin/rsync" ${sourcedir} ${TUSER}@${TIP}:${targetdir} 
    if [ $? == 0 ] ; then
     syncstatus="Synchronization of ${sourcedir} was successful!"
     syncstatus="Synchronization of ${sourcedir} had some errors $!"
    echo scp ${sourcedir}/rsync.log ${TUSER}@${TIP}:${targetdir}/${targetfolder}
    /Applications/terminal-notifier_1.4.2/ -message "${syncstatus}" -group Syncfolders -title Syncfolders             
    Now get a 'throughput of 34MB/s' (yes, capital MB) over a Powerlan network due to effiency of rsync :)
  15. el-John-o thread starter macrumors 65816

    Nov 29, 2010
    Well I'm already getting faster than that! With my NAS I'm hitting 105-110MB/s (yes, capital MB!)
  16. glenthompson macrumors 68000


    Apr 27, 2011
    The only thing I keep in a Windows VM is the OS and applications. I have a backup of the configuration. All my files are stored in the Mac environment. I exclude the Parallels VMs from being backed up by TM.
  17. el-John-o thread starter macrumors 65816

    Nov 29, 2010
    Yep. All of my files are kept elsewhere too.

    Again, I've long since found the solution. This was purely a convenience thing. Should my hard disk or otherwise fail, I can use time machine to go right back where I was- time machine and all-, and parallels built in snapshot feature mentioned a while back is the ticket.

    I appreciate the input though! I mostly use time machine as a hope-I-never-need-it convenience. The ability to go right back to where I was. Everything of value, though, is kept on a NAS and mirrored to a cloud backup.

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