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Failed incremental backups - restore point options RRS feed

  • Question

  • Currently I'm doing a full backup once a week in a Friday night and incremetnals for the remainer of the week, and hava few questions

    1) If an incremental backup was to fail the data that it was able to backup up to the point of failure, doesn't show up in DPM as a restore point, for example if a 100GB backup failes at 90GB though the job, is any of the backuped data restorable?

    2) How do incremental backups work, does it rely on the archive bit for the files , does it reset the archive bit during the backup or post process?  and how does that work in the event of a failed incremental.

    3) If an incremetnal of full backup fails and I retry the job, does it continue from the point of failure or restart the job from scratch (and how do previously backuped up incrementals play in to this relating to the archive bit)

    Thursday, February 17, 2011 4:30 PM

Answers

  • Hi,

    We never commit the write after the backup fails, so there is nothing to read or import.  Next tape backup job that selects that tape will start writing where the last successful tape backup completed.


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Friday, February 18, 2011 9:06 PM
    Moderator

All replies

  • Hi Steve,

     

    A1)  No, since it wass not a successful backup, we don't consider it a recovery point.

    A2) DPM does not use archive bit, that is old school, we use the NTFS USN Journal to determine what files have changed since the last backup.

    A3) If you restart the job, we start from the beginning and backup all files that have changed from the last successful backup.  Archive bit is not touched as a result of any backup operation done by DPM.


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Thursday, February 17, 2011 6:10 PM
    Moderator
  • Thanks for that, can you let me know if for instance a backup to tape were to fail at, say 90% complete, is there a way to import the contents of the what had been backed up to tape into DPM to create a recovery point to perform a restore from? 
    Friday, February 18, 2011 8:59 PM
  • Hi,

    We never commit the write after the backup fails, so there is nothing to read or import.  Next tape backup job that selects that tape will start writing where the last successful tape backup completed.


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Friday, February 18, 2011 9:06 PM
    Moderator