Issue on 4 GB file limit for DVD storage

Discussion in 'Acronis True Image Product Line' started by jctay, May 8, 2009.

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  1. jctay

    jctay Registered Member

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    I am running on 32-bit XP sp3 and Acronis TIH latest build 9707. I switched to TIH 2009 recently. Prior to this I backuped my system with Symantec Ghost 11.

    4 GB file size limit
    Currently, the 4 GB file size limit of the tib file is defaulted to 4,294,966,784 bytes.
    Under file property in windows xp,
    Actual size: 3.99 GB (4,294,966,784 bytes)
    Size on disk: 4.00 GB (4,294,967,296 bytes) = (2 to the power of 32) bytes, exactly.

    No issue was encountered when moving files between hard disks or USB removable storages, either in FAT32 or NTFS file system. Tib file of this size can be saved to DVD under UDF file system without problem, for instance, using NERO burner.

    When burning data to DVD, however, this file size exceeds the size limit to create a useful ISO file. Although the ISO file can be created and burnt to DVD successfully but the tib file of this size cannot be copied from the DVD due to file corruption. Acronis TIH failed to validate these archived files on the DVD, too. By the way, I tested with latest version of UltraISO, ver 9.3. The reason to burn ISO file to DVD is that it allows a bootable DVD backup to be created easily.

    For GHOST 11, the spanned files are limited to 4,278,190,080 bytes by default. I have no problem to save these files to DVD with any ISO DVD burner.

    Suggestion
    Above issue can be overcome if archive splitting during backup is manually preset to 3.99 GB (actual size is 4,284,229,632 bytes). I hope the Acronis support personnel can look into it -- reducing the present 4GB limit's default size.

    With warmest regards,
    jc
     
  2. jehosophat

    jehosophat Registered Member

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    Welcome to the forum.

    You made some interesting points, thanks.

    Acronis is basically set up for backing up to hard disks not media like CD or DVD. Restoring from multispanned backups cd or DVD is more risky than from one source and involves multiple changes of media.

    The Acronis joke is that your dvd drive will wear out before you do the last dvd swap and complete a restore. If you have a backup over 3 dvds you wont just insert the dvds once each.

    Backup to for example USB drives, network drives, caddy based internal secondary hard drives and other internal drives is where you should backup to rather than DVD. The life expectancy of DVD media is not as long as a hard disk.

    You can never have too many backups though, so using DVD's is understandable. If you do backups to DVD's then I suggest that they are always done using the 2 step approach: write files to a hard disk first then copy to dvd.

    My experience with Acronis validation of DVD's, is that validation is worthless, as I have had dvd's validate and 60 seconds later refuse to restore.

    USB hard disks are now relatively cheap, so I think DVD backup is better than no backup but not the preferred media to use.
     
  3. DwnNdrty

    DwnNdrty Registered Member

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    And to add to the 2-step approach, many here split the backup at 1492Mb. Three of these splits fit on a dvd with very little waste and you get around the UDF issue.
     
  4. jctay

    jctay Registered Member

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    Re: Issue on 4 GB file size limit for DVD storage

    Thanks for the pointers and the magic number. :)

    My little observations
    After executing the 2-step approach, the tibs files that were saved into DVDs passed the validation process.

    However, when the tib files were deleted from the hard disk, those in DVDs failed the backup archive validation.

    By copying the full set of backup archived files from the DVDs to the same directory in the hard disk, both validation and recovery were successfully completed.

    Go figure it out & Good luck.

    Cheers.
     
  5. DwnNdrty

    DwnNdrty Registered Member

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    Re: Issue on 4 GB file size limit for DVD storage

    Yes, I believe the consensus is that you have to put back the files on to the hard drive also to do a Recovery (as well as a validation). I don't use opticals at all for TI backups so can't confirm this.
     
  6. seekforever

    seekforever Registered Member

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    Technically speaking, you shouldn't have to copy the DVD tibs to do a validate or a restore but in practice, copying is the only way I would consider doing it. I have validated DVDs directly but it was back a couple of versions or so. I don't really bother with DVDs anymore. Even my backups for "off-site storage" are put onto a spare old IDE HD for safe-keeping at my friend's house.
     
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