Why Does Differential Backup Grow So Fast?

Discussion in 'Acronis True Image Product Line' started by rraisley, Nov 6, 2008.

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  1. rraisley

    rraisley Registered Member

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    I perform a daily differential backup Images on my 2 hard drives (to a 3rd hard drive) using True Image Home V11. On my C (Windows) drive, the size of the differential backup only increases by 50 to 200 MB per day. The Differential backup on my D-drive, used for data and My Documents, increases in size by 1 GB or so each day. With very few exceptions, I'm not changing anything! I doubt there is 50 MB of files that change, in fact would expect more to change on my C drive. And if it's due to fragmentation (as I'm using an Image), it would be much greater on D.

    How do I find out what files are being changed, and added to, the daily differential backup on D? I've restored complete drives, but not usually individual files? Is there some way I can determine what new files are included in the backup? Most of the files haven't been changed since the original (full) backup, yet when I choose any date, I see files to select that haven't changed at all?
     
  2. jmk94903

    jmk94903 Registered Member

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    What operating system are you using?

    Do you have an automatic defragmenting program running? (Vista will defragment automatically by default).
     
  3. rraisley

    rraisley Registered Member

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    Vista Ultimate 32-bit. Automatic indexing is turned OFF. And surprisingly, this doesn't happen to my c-drive (Windows), just my data drive (which changes rarely).
    I have PerfectDisk defragmenter, and it is run manually, only when I'm going to do a FULL backup using TI.
     
  4. seekforever

    seekforever Registered Member

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    Are you sure the Vista defragmenter is indeed turned off?
     
  5. rraisley

    rraisley Registered Member

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    Yes. And if it weren't, there would probably be more a problem with the C-drive.
     
  6. K0LO

    K0LO Registered Member

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    One thing you could try is to run chkdsk D: /R on your data partition to be sure that there are no bad sectors or file system errors on the partition. These may cause TI to consume more space for the differential image.
     
  7. Brian K

    Brian K Imaging Specialist

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    Is the used space in your D: drive increasing each day?
     
  8. rraisley

    rraisley Registered Member

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    I haven't been keeping track. I've recorded it today, and will keep track of it. The size of the differential backup increased by 1.1 GB from yesterday to today. I haven't change, or created, more than a few MB of files during that time.

    I thought perhaps it was my 5.5 GB paging file, which obviously changes daily, but when I excluded it, it made no difference.

    Maybe I should switch to incremental backups for a bit to test. Can I get a listing from TI of what files changed on any given day from the previous day?
     
  9. Brian K

    Brian K Imaging Specialist

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    As mentioned above, defrag does this. Is it possible D: is getting defragged and C: isn't?

    Windows System Restore points can also do it and you could see your D: drive used space increasing by 1 GB plus each day. Wait for a few more days to assess what is happening.

    You can keep track of changing files with TreeSize.

    http://www.jam-software.com/freeware/index.shtml
     
  10. rraisley

    rraisley Registered Member

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    I don't think so. No, it isn't.
    That is a definite possibility. I hadn't thought of that. I also notice I seem to have a lot more Previous Versions on my D drive than my C drive.
    Good tool. I downloaded it and will use it to keep track. The Restore points are a definite possibility.

    Thanks a lot.
     
  11. Brian K

    Brian K Imaging Specialist

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    With TreeSize you can "Save Report as XML"
    Tomorrow you can "Compare with XML Report" and you will see which files have been added/deleted.

    (Maybe only from the Pro version)
     
    Last edited: Nov 8, 2008
  12. rraisley

    rraisley Registered Member

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    Yeah, those features are only available with the $50 Pro version.

    One thing I'm noticing, though, on the printed report (it's not as obvious on screen) is that when looking at my D-drive, there is a huge difference between the bytes in "This Folder: 60,460 MB", and "Used: 132,231". While on my C-drive it's very close at "This Folder: 88,900 MB" and "Used: 85,852 MB". I'm thinking there are ~70 GB of space on my D-drive not really counted by TreeSize (and therefore maybe hidden/system/restore files?). As my D backup file from TI is 105 GB (while C is 60 GB), it's obvious to me there is some area, uncounted by TreeView in the "This Folder", but used on the hard drive, AND backed up by TI. It may well be System Restore, as mentioned. If so, I don't think I'd want to back it up, as I'd use /either/ System Restore, OR restore the whole hard drive.

    Any idea where System Restore files are, and how to exclude them from TI?
     
  13. Brian K

    Brian K Imaging Specialist

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    I turn System Restore OFF on all partitions but I think the files are in the System Volume Information folder. How large is that folder?
     
  14. rraisley

    rraisley Registered Member

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    Okay, looking a bit further: My D-Drive Properties says that 128 GB are used. However, examining all directories on the drive, even hidden ones, tells me only about 60 GB of space is actually used. The difference of almost 70 GB has to be some sort of hidden System files, hidden to the point that they are in no "real" directory or root. Maybe even in some sort of "partition" (not a real one - as I don't have any on that drive, but something the OS uses.

    That's the only thing that makes sense to me. And if it is System Restore, then it makes sense that would be increasing each day. But to do an image, there seems to be no way to exclude this hidden area that takes up so much space (and appears to be increasing daily).

    The best way to eliinate this would no doubt be to use a File backup from TI, rather than an Image. But I've always had very poor results from File backup. While it currently takes just 5 minutes to make a 12 GB differential Image backup of my 130 GB data, it takes hours to do the same thing with a File backup. Basically, I've had very poor luck even making a file backup of just a couple directories with TI, and have even been looking at other backup programs because of that.
     
  15. rraisley

    rraisley Registered Member

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    My tools say that folder has nothing in it (even TreeSize says this). But I suspect that its contents are simply not accessible by the user, and it shows none due to that.
     
  16. Brian K

    Brian K Imaging Specialist

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    To check for hidden files...

    Tools, Folder Options, View Tab,
    dot in Show hidden files and folders,
    NO tick in Hide protected OS files.

    Can you see System Volume Information now?
     
  17. rraisley

    rraisley Registered Member

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    That is the way my system is set, but Vista won't show you any information there.

    But I just did a test. I changed my backup of D to Exclude all system files and folder, and did a Differential backup. Instead of 12.7 GB file like I got last night, I now get a 247 MB file! So, it's absolutely the System files that are causing it, probably from something like System Restore.

    Now, I don't consider excluding system files on C a safe thing to do; if I need to restore the drive, it will NEED the system files. But, for some reason, there is little difference in size on C. But on my D (non-Windows) drive, would doing a backup ane excluding system files be okay? What is considered "System" files? I have a lot of programs installed on D, and some will include runtime files and all, but if they're not really System files, that might work. Oh, and if I restore a data drive, excluding System files, will that not restore the FAT (or whatever file organization structure Vista uses), making the files inaccessible? Wouldn't make sense that it would, but...
     
  18. Brian K

    Brian K Imaging Specialist

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    I think you need to know the nature of these files before deciding what to do next.

    Are you sure there is no tick in Hide protected OS files? The default is a tick.
     
  19. K0LO

    K0LO Registered Member

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    rraisley:

    If you want to view these files, browse (not mount) a recent backup by double-clicking on it. Navigate to the System Volume Information folder and you can see what's there.

    You can safely exclude System Restore Point files from your Data partition backup. Unless Acronis has fixed this problem in TI 2009, the restore points will be deleted when you restore the partition anyway; at least that's how it's worked with versions 10 and 11. So it makes absolutely no sense to include them into an image if they are not going to survive restoration. Here is a recent post with information on how to exclude only the restore points from the System Volume Information folder.

    You must have a very large archive of "Previous Versions" on your data drive. One other suggestion is to reduce the space occupied by system restore on this volume. I am able to get about 60 days worth of "Previous Versions" in 6 GB of space, but everyone's usage habits will be different. If yours go back by 90 or 120 days or more then you may want to consider reducing the space used by system restore. To see how much space you are using for restore points on each volume, start an elevated command prompt and type "vssadmin list shadowstorage".
     
  20. rraisley

    rraisley Registered Member

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    Okay, yes there are a bumch of files in the System Volume Information folder, but using the hint in the link, to exclude only those that begin with "C:\System Volume Information\{*" actually increased the backup size quite a bit. It was 12.7 GB last night, only 0.25 GB by excluding System files, but up to 15.9 GB including system files but with the above exclusion. Not a step in the right direction.

    I'm reading that the System Volume Information folder has basically two things: System Restore information, and Indexing information. I don't feel I need either one, so may just exclude System info.

    Whoops! My (extremely stupid) error. Including "C:\System Volume Information\{*" did help my D-drive backup much. lol! Changing it from C to D went back to 0.4 GB. Which is fine.

    Okay, I'm in business then. Simply excluding the System Restore copies, which as everyone says, are lost whenever doing a full TI restore anyhow, is the way to go. Very quick, small Differential backups. Definitely the way to go.

    Thanks everyone SO much for helpimg me with this, and getting to the bottom of the growing backups.

    Now, if only I could figure out why my C drive only has a single Restore Point (and very little space used), while my D drive has bunchs, with a lot of space used. ;-)
     
  21. rraisley

    rraisley Registered Member

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    Found it:

    vssadmin resize shadowstorage /On=C: /For=C: /Maxsize=10GB

    limits the System Restore size on C to 10 GB. Turns out my C drive was set at 1.5 GB, my D drive 75 GB. I reset C to 10 GB, D to 30 GB, which is more than enough.

    To see what the settings are usage are, use:

    vssadmin list shadowstorage

    Both of these are typed into a Command Prompt window with admin privilages.

    This also answers what that huge unmovable area is on my defragger! ;-)

    One last question: I see TI 2009 is out (I'm using TI 11). Any reason to upgrade for my usage? I haven't received an upgrade notice or anything, but maybe it's so new I just haven't gotten it yet.

    Again, thanks to everyone to hep find an answer to my questions. I'm better off now, AND better informed. A good combination! ;-)
     
  22. K0LO

    K0LO Registered Member

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    It's nice to see the pieces of the puzzle fall in place. What you've found out makes perfect sense.

    I would love to be able to exclude Restore Points from my images, but TI version 10 doesn't have that feature. I'm reluctant to upgrade given that version 10 build 4942 is probably the best release of TI yet, and both TI 11 and TI 2009 have introduced many new problems along with their new features.
     
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