Forum Discussion

Linda_Lounsbury's avatar
10 years ago

Full Backups/Incremental vs. Full Backups/Differential Backup Scenarios

Our situation:

We are running BE 2010 on Win 2003 server.  We have LT05 and LT04 tape drives.

We have a file server that contains approximately 900gbs of data, for which we do weekly full backups and daily incremental backups.  The incremental backup size averages between 2 and 4gb of data per backup.  Due to the size of the full backup I am having to change tapes more freqently.   I am considering going to a monthly Full backup and daily differential backup scheme.  Since differential backups are cummulative, would my final differential backup of the month be between 40 and 80 gbs (assuming 20 differentials between full backups)?

From what I have read, it seems like a combination of monthly full backup and daily differential backups is a good combination from a restore point of view.

I welcome and solicit your comments.  I guess my ultimate goal in changing the backup scheme is to reduce the number of tapes I am using throughout the month.  I have read the blog from PKH on the Pros and Cons of Various Backup Schemes.

thanks,

Linda

  • Your estimation is about right and differential backups do make restores easier.  Does your backup window allows you to do differential backups?  The differential backups would take longer than incremental backups.

    Also, I don't see how going to differential backups would solve your problem of frequent tape changes.  In fact it would make it worse since each differential would be a lot bigger than the incremental.

    You might want to take a look at tape libraries.

  • Hi Linda,

    PKH is correct. In addition to what he had mentioned, try to check or verify your retention period under Media Sets. By lowering your retention periods, this might help lowering the amount of time the backup data will be protected from overwriting. Thus lowering the number of tapes needed.

    Below TN explains Overwrite Protection Period and Append Period.

    http://www.symantec.com/business/support/index?page=content&id=TECH5459

     

    Regards,

    Adonis

  • Your estimation is about right and differential backups do make restores easier.  Does your backup window allows you to do differential backups?  The differential backups would take longer than incremental backups.

    Also, I don't see how going to differential backups would solve your problem of frequent tape changes.  In fact it would make it worse since each differential would be a lot bigger than the incremental.

    You might want to take a look at tape libraries.

  • Hi Linda,

    PKH is correct. In addition to what he had mentioned, try to check or verify your retention period under Media Sets. By lowering your retention periods, this might help lowering the amount of time the backup data will be protected from overwriting. Thus lowering the number of tapes needed.

    Below TN explains Overwrite Protection Period and Append Period.

    http://www.symantec.com/business/support/index?page=content&id=TECH5459

     

    Regards,

    Adonis

  • Hi All,

    Thanks for answering my questons.  Changing my retention time/Overwrite Protection Period is not an option at this point.

    I'll have to give this more thought.  I really do like the idea of differentials from a restore perspective, but I can see that they may not relieve my tape usage problem.  I probably should just move this backukp process to our higher density tape drive.

    Thanks again.

    Linda