Deleting Old Differential Backup Files

Discussion in 'Acronis True Image Product Line' started by georged, Jan 21, 2008.

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  1. georged

    georged Registered Member

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    Hi there,

    I have TI 11 and keep a full backup of both my hard drives on two external USB drives. I only use differential backup.

    I notice that after I update the differential backup, a new differential backup is created in the same folder as the full backup.

    Is it OK to delete the old differential backups created before the most recent one?

    Thanks for any help.
     
  2. shieber

    shieber Registered Member

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    Yes and no. You don't need the obsolete diff file(s) for restore but you do to use the Validation feature in ATI. Go figure. Probably it's a result of how the original code was written and it's too involved for ATI to rewrite it.
     
  3. TheWeaz

    TheWeaz Registered Member

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    In addition to what shieber mentioned, note that deleting any of the DIFFs will limit your restore options. Leaving only the FULL and one DIFF, you can only restore to the dates that those two files were created; nothing in between. May or may not be an issue for you.
     
  4. TenOC

    TenOC Registered Member

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    As I understand, the last Diff will have ALL the file modified or created since the full o_O?? o_O You only lose the versions (?) or files deleted in between.
     
  5. MudCrab

    MudCrab Imaging Specialist

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    That's correct.

    For example:
    You have a file named FileA.doc.
    You create a Full backup image on 01-18 that contains FileA.doc.
    You create a Differential backup on 01-19 which contains an updated FileA.doc.
    You create a Differential backup on 01-20 which contains an updated FileA.doc.
    You create a Differential backup on 01-21 which contains an updated FileA.doc.
    You then delete the 01-19 and 01-20 Differential files.
    You can only restore any files that are in the original Full or the last Differential images.

    The FileA.doc version from the 19th and the 20th can't be restored. You'll only be able to restore the versions from the 18th and the 21st.
     
  6. shieber

    shieber Registered Member

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    and just to belabor what might be obvious to some and note others, restoring using the 1-18 file will give you the full with all the changes in effect as of the 18th and restoring using the 1-21 file will give you the full with all of the in effect as of the 21st. Interim changes that came and went inbetween (like a file created on the 19th and deleted on the 20th), and therefore not in effect on the 21st won't show up in the restore.

     
  7. georged

    georged Registered Member

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    Thanks for the info.

    I'm only really interested in the full backup and the most current differential. So, from what is being said, I can delete all the interim differentials and still have a backup of my PC that is fully up to date as of the most recent differential.

    Great stuff. Bye for now.
     
  8. shieber

    shieber Registered Member

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    That's correct. If you want the latest, then the full plus latest diff file are all you need. You can't do validatons for the reason cited but then, validations aren't all they're carcked up to be anyway.
     
  9. stevewa

    stevewa Registered Member

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    I am confused about this also. I am using True Image 9.1 Workstation, and have scheduled 2 tasks. 1 occurs each night at 3 am to do an incremental backup, and 1 on sunday morning at 1:30 am to do a full backup.

    I have read the KB articles about the difference between incremental and differential, but they only seem to talk about storage space issues and restore speed.

    What I'm considering is, if I do a full backup once a week, but then 3 weeks later discover that I want a file that was deleted 3 weeks ago, will that file not be able to be restored because I do a weekly full backup, and since it was deleted before the full backup was run, it won't show up as a file to be restored becaus eit was not on the disk at the time the full backup was run? Does a full backup make previous incrementals and differentials obsolete?

    Is it better to start with a full backup, and then do incrementals everynight, to give yourself the option of restoring single files?

    I've read that restores using incrementals would take a long time to do a recovery on bare metal, but that is not as long as rebuilding the computer from stratch.

    And all my backups are done to a second hard drive (320GB, identical to the boot drive) that is a acronis secure zone (the secure zone occupies the entire disk). So in that case I can't "see" any of the differentials or incrementals to be able to delete them, correct? I just let acronis manage them using the "delete the oldest backup snapshot to make room for the newest backup" method. The only thing I can figure out to do it use the scure zone manager to increase or decrease the storage size, but I can't "see" inside it to look at what is there (and I probably never want to if acronis works automatically)

    (sorry for the long post, i find it helps to be more verbose instead of having to post multiple times to fill in the blanks.)
     
  10. TheWeaz

    TheWeaz Registered Member

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    “I can't "see" inside it to look at what is there”
    That’s why it’s called a Secure Zone. If you step through the restore wizard, it will show you the files, dates and types of the backups.

    “What I'm considering is, if I do a full backup once a week …”
    What name have you given these backup images you’re creating? If you use the same name for all of them, then they’re writing over each other and no, you can’t go back 3 weeks.
     
  11. stevewa

    stevewa Registered Member

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    I haven't tried to recovery step yet, but after your posting I stepped thru a few screens and yes sir, you can see what is in the secure zone. thanks

    Now I have only done 3 backups so far, 1 is the full backup, the other 2 are the incrementals.

    In the recovery wizard, I don't see anyway I could delete any of the backups even if i wanted to, so I don't need to worry about it.

    If I have to rebuild everything from scratch, do I first select the main backup, and then after that is done being restored, do I have to do it again for each of the incremental backups?

    And since I am using the secure zone, it doesn't give me the option to specify a backup name, so I don't think it is overwriting them, just keeps adding new ones based on the date and time of the backup.

    So it appears I may be able to go back 3 weeks to try to recover a file., since I am using the incremental mode right now. I'll give it a test on Monday to see how my theory works.
     
  12. MudCrab

    MudCrab Imaging Specialist

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    Just select the backup image of the date you want and restore it. TI will restore everything in one step. For example, if you select the 3rd Incremental image, TI will restore the Full, 1st, 2nd and 3rd Incremental images in one pass.
     
  13. TheWeaz

    TheWeaz Registered Member

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    "And since I am using the secure zone, it doesn't give me the option to specify a backup name, so I don't think it is overwriting them, just keeps adding new ones based on the date and time of the backup."

    Try running the FULL again and then step through the restore wizard and see what files you have available for restore. I believe that you’ll find that rerunning the FULL task will overwrite the existing image.
     
  14. noimage

    noimage Registered Member

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    A related question - I have it set up to do differential backups, and then a full one after a couple of differentials. How do I tell one from the other in my backup folder? Just the size? The file names are almost identical.
     
  15. shieber

    shieber Registered Member

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    Do you personally need the Secure Zone? If you don't have to have it, just get rid of it and do yur backups to some normal partition. You can view, copy, delete, the backup files just like any other files, using windows explorer, if that's what yu want to be able to do. If you want ATI to manage the number of backups, yuo can do that too without using a SZ -- use Backup Locations instead.

    If high security is an issue, save the backups somewhere truly safe, like a an external dirve you can lock away somewhere safe. An sz can be wiped out with formating, disk editor, and other sometimes unintended disk actions. You don't get much for the pita that SZ present, imo.
     
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