Incremental backup size

Discussion in 'Acronis True Image Product Line' started by geohei, Jan 25, 2007.

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  1. geohei

    geohei Registered Member

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    Hi.

    When doing an incremental backup, I noticed that even after minor changes to the partition, the incremental backup is about 80% of the size of the full backup.

    How is this possible?

    I was expecting something like 10-20% since only the changes are backed up.

    Thanks,
     
  2. Mem

    Mem Registered Member

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    Do you have a defragmentor working in the background? That would change the sectors on the disk and give much larger incrementals than you would expect from normal PC use.
     
  3. geohei

    geohei Registered Member

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    Not that I know.

    Is there any any WinXP background task which defrags automatically?

    Thanks,
     
  4. Mem

    Mem Registered Member

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    No, the built in defragger doesn't do that. My full image is about 11 GB with daily incrmentals in the 0.3 to 0.5 GB range just to give you a reference point.
     
  5. geohei

    geohei Registered Member

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    These are the values I expected as well.

    Are you doing the backups via the CD (OS down), or while the OS is running?

    Look at this here:

    Y:\>dir
    Volume in drive Y is DRIVE IMAGE
    Volume Serial Number is CF62-8E57

    Directory of Y:\

    20.12.2006 13:09 3.690.118.507 CD_WinXP_01_2.tib
    25.12.2006 06:52 3.134.024.797 CD_WinXP_01_3.tib
    05.11.2006 16:01 3.910.823.931 CD_WinXP_01_.tib
    3 File(s) 10.734.967.235 bytes
    0 Dir(s) 10.721.558.528 bytes free

    Any idea why my incremental backups are that high?

    Thanks,
     
  6. Mem

    Mem Registered Member

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    I'm running as an automated task each night from within Windows XP. Other than the defrag issue I don't have a clue why your seeing such high numbers, sorry.
     
  7. GianniC

    GianniC Registered Member

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    I was just wondering if you use NTFS compressed files. Every time you open a compressed file it is decompressed and later compressed again in a new location on the disk... For sure if you change even a single byte.
    I know it caused lots of fragmentation on W2k. Perhaps it can be the cause.
     
  8. geohei

    geohei Registered Member

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    @Mem
    Thanks for your help

    @GianniC
    No compressed files, but the 2 partitions (C:\ and D:\) which I backup are located on a RAID1 onboard system. Could this possibly be the reason?

    What about backing up with running OS and from the CD (OS is down). Does this make a difference?

    Thanks
     
  9. GianniC

    GianniC Registered Member

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    I have multiple partitions on multiple disks too.
    My D: partition is on a RAID 1 disk; I make a monthly full backup and a differential backup every week.
    I save my backups on the removable HD.
    I don't have any problem with backup sizes.
    My full backup uses 35GB and differentials grow from 2GB to 7GB.

    Just a note on the example you post

    20.12.2006 13:09 3.690.118.507 CD_WinXP_01_2.tib
    25.12.2006 06:52 3.134.024.797 CD_WinXP_01_3.tib
    05.11.2006 16:01 3.910.823.931 CD_WinXP_01_.tib
    3 File(s) 10.734.967.235 bytes

    There are 50 days between the full backup and the first incremental.
    If you have used your PC during that time, the 90% of changes could be not so surprising.

    Here is what I mean.

    A 3.9GB full backup containing all your software and data, should mean that most space on your HD is used by Windows XP, installed programs, internet caches, temp files and system restore files.

    Windows XP and MS software is updated monthly, while the position of system dlls on HD is optimized after every update (windows prefetch); internet caches and temp files are very volatile and you could have updated part of the remaining software during all those days.
    Well, the first incremental at 3.7GB could be ok.

    The second incremental is more difficult to explain. I believe TI has decided the first incremental is too different from the baseline and has made a differential instead. Just a thought.
     
    Last edited: Jan 26, 2007
  10. astefan

    astefan Registered Member

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    Hi, I am confused about the same issue. Well, just my 2 cents:

    What about the pagefile.sys (1,5GB) and the hiberfil.sys (1GB)? They get modified nearly every minute / day. They are on my c: drive as well and when I generate an image they are included, aren't they? So the image have to be large than 1GB...

    I am wrong?

    Cheers,
    Stefan
     
  11. thomasjk

    thomasjk Registered Member

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    These two files are not included only a placeholder for each.
     
  12. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello geohei,

    Thank you for choosing Acronis Disk Backup Software.

    We are sorry for the delayed response.

    Please note that as GianniC mentioned the incremental or differential backup created after an active usage of operating system might be considerably larger than usual. Please also have a look at this thread for details.

    Thank you.
    --
    Marat Setdikov
     
  13. geohei

    geohei Registered Member

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    Are you sure there is nothing like an automatic degragmentation mechanism inside windows?

    See here.

    Thanks,
     
  14. Brian K

    Brian K Imaging Specialist

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    Could we hear from people who do daily incrementals and are satisfied with the results. What are the sizes of your incrementals (as a % of the baseline image) in the defrag and no defrag situation?

    Most of our information on this topic comes from people who aren't satisfied with the result. What should we expect from TI?
     
  15. GianniC

    GianniC Registered Member

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    From what I remember about this matter, Windows should automatically defrag only files listed in "C:\WINDOWS\Prefetch\Layout.ini".
    This files should be compacted in a contiguos part of the HD, for a quicker boot process and application launch.
    Usually only a small part of HD is involved. For example, in my PC there are about 77,000 files, but less then 3,000 in Layout.ini
     
  16. seekforever

    seekforever Registered Member

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    If System Restore is enabled it can use up to about 12% (default) of your partition size for storing restore points.
     
  17. Brian K

    Brian K Imaging Specialist

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    Mem,

    I missed your post. Thanks for those numbers.
     
  18. Tsu

    Tsu Registered Member

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    7 day backup cycle.. 1 full followed by 6 increminatal, wash, rinse and repeat.

    Incremental size depends on what ya bin do'in during the day. One example below is a Dell notebook that runs all day mostly doing nothing. On the second example on Feb 8 I must have done a bunch or torrents, warez or pron downloaing..bwahhahhahhahhaha. More likely I did a disk clean up including deleting all the system restores except the last one.

    These are both XPPro C: (system ) drives only.
     

    Attached Files:

    Last edited: Feb 9, 2007
  19. Brian K

    Brian K Imaging Specialist

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    Tsu, thanks. They are very acceptable sizes.
     
  20. geohei

    geohei Registered Member

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    Is this one ok as well (WinXP under normal operation)?

    Code:
    13.02.2007  05:06     3.213.466.624 cd.tib
    14.02.2007  05:01       106.406.400 cd2.tib
    15.02.2007  05:01       258.870.272 cd3.tib
    16.02.2007  05:01       301.061.632 cd4.tib
    17.02.2007  05:04     1.323.952.640 cd5.tib
    18.02.2007  05:01       108.037.120 cd6.tib
    19.02.2007  05:03       450.027.520 cd7.tib
    20.02.2007  05:01       188.531.200 cd8.tib
    21.02.2007  05:01       161.792.000 cd9.tib
    22.02.2007  05:01       503.903.232 cd10.tib
    23.02.2007  05:01       155.237.888 cd11.tib
    24.02.2007  05:01        97.559.040 cd12.tib
    25.02.2007  05:01       153.438.720 cd13.tib
    26.02.2007  05:20       209.394.688 cd14.tib
    27.02.2007  05:02       216.814.080 cd15.tib
    BTW ... here an article about automatic defragmentation within WinXP:
    http://groups.google.com/group/micr...defrag heinesch winxp&rnum=2#a954d17f65167807

    Thanks,
     
  21. geohei

    geohei Registered Member

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    Here some more details about my issue (sorry for the late followup, but i was quite busy ...).

    I managed to nail down the problem a little bit. The incremental backup is only so big, after I restored the original backup. I explain ...

    - stable system -> backup1
    - I test software ... system gets dirty
    - after I figured out which software I would like to install, I restore backup1
    - after backup1 is restored, I install the software
    - backup2 (incremental) is generated (again I have a stable system)

    Here an example:
    Code:
    26.03.2007  12:37     3.772.153.415 i_test.tib
    26.03.2007  13:00         1.103.149 i_test2.tib
    27.03.2007  07:38     2.541.380.767 i_test3.tib
    i_test: initial full backup
    i_test2: incremental system right after i_test was created. Very small only!
    i_test3: incremental backup after i_test2 was restored. Huge!!!

    Why is a restore with succeeding incremental backup blowing up that much?

    Thanks,
     
  22. geohei

    geohei Registered Member

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    Hi.

    No answer yet ... :'(
    Does nobody know the answer, or was the question unclear (shall I rephrase)?

    Thanks
     
  23. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello geohei,

    We are sorry for the delayed response.

    Note that when Acronis True Image restores a disk\partition images it does not place data to the exactly same sectors it resided originally. And, as it was described, Acronis True Image operates on a sector level backing up sectors of the hard drive and information about it's geometry. Thus, when you perform incremental\differential backup after you restored the full backup the incremental\differential backup will be considerably larger than usual.

    Thank you.
    --
    Aleksandr Isakov
     
  24. geohei

    geohei Registered Member

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    That explains it all.

    May we know why Acronis TI doesn't restore the data to the same place (I was actually quite surprised to hear this)?

    Is there any option to enable restoration to the same place?

    Thanks,
     
    Last edited: Mar 30, 2007
  25. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello geohei,

    Please notice that restoring not to the same place in this case means data gets partially defragmented in the process. There are no changes on the filesystem level.
    The data will get restored to the same place only in case Acronis True Image cannot recognize the filesystem, and restore is destined to the same hard drive (same physical structure).

    Thank you.
    --
    Marat Setdikov
     
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