Differential Backups - Veritas Net Backup

This is a discussion on Differential Backups - Veritas Net Backup ; Hi Folks, Here is my scenario and question: I have 4 fileservers. TL with one tape drive Tape Capacity 400/800GB Is it best for me to do a FULL Backup once a week (SAT nights) and then a Differential nightly ...

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Thread: Differential Backups

  1. Differential Backups


    Hi Folks,

    Here is my scenario and question:

    I have 4 fileservers.
    TL with one tape drive
    Tape Capacity 400/800GB

    Is it best for me to do a FULL Backup once a week (SAT nights) and then a
    Differential nightly or Incremental?

    Also, is it better to have the same tape set (Volume Pool) for the FULL and
    DIFFERENTIAL Backups or seperate? Reason being, the FULL file Backup is about
    290GB...so I was thinking that backups could go on the same tape(s) because
    of the native tape size.

    Any thoughts or help from experience is appreciated.



  2. Re: Differential Backups

    Jason wrote, in part, on 5/29/2006 3:55 PM:
    > I have 4 fileservers.
    > TL with one tape drive
    > Tape Capacity 400/800GB
    >
    > Is it best for me to do a FULL Backup once a week (SAT nights) and then a
    > Differential nightly or Incremental?


    Forget "differential" backups. You want a restore to depend on as few
    parts as possible.

    > Also, is it better to have the same tape set (Volume Pool) for the FULL and
    > DIFFERENTIAL Backups or seperate? Reason being, the FULL file Backup is about
    > 290GB...so I was thinking that backups could go on the same tape(s) because
    > of the native tape size.


    Unless there are other considerations, I'd have one pool. I don't see
    the "Full being a significant portion of a tape" as much as
    "Incrementals are a tiny portion of a tape". Writing just incrementals
    to a tape might mean writing to one tape for a relatively long time,
    meaning one tape failure affects lots of client servers over a long
    time. Putting them together means that I'll pretty much be assured of
    different tapes every couple of weeks or so.

    But what's really important is getting your backup schedules and
    retentions right in support of your business needs and expectations.

    Hope this helps!

    cheers, wayne

  3. Re: Differential Backups


    "Jason" wrote:
    >
    >Hi Folks,
    >
    >Here is my scenario and question:
    >
    >I have 4 fileservers.
    >TL with one tape drive
    >Tape Capacity 400/800GB
    >
    >Is it best for me to do a FULL Backup once a week (SAT nights) and then

    a
    >Differential nightly or Incremental?
    >
    >Also, is it better to have the same tape set (Volume Pool) for the FULL

    and
    >DIFFERENTIAL Backups or seperate? Reason being, the FULL file Backup is

    about
    >290GB...so I was thinking that backups could go on the same tape(s) because
    >of the native tape size.
    >
    >Any thoughts or help from experience is appreciated.
    >
    >


    The choice between DIFF and CUM is based on how fast you want your backups
    to go vs how fast/convenient you want your restores to go. The more important
    the latter, the more likely you'll want to use Cumulative INCRs because then
    to do a restore you only need the latest FULL + the latest INCR [vs all INCRs
    since the last FULL if you were doing Differential].

    We don't separate FULL and INCR into different pools where I am - too much
    of a hassle with several hundred clients. I don't know if different pools
    will gain you anything: even if they used the same pool, because the retention
    periods are likely different between INCR and FULL, the data might get written
    to different tapes anyway.


    Scott

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