Data Protector 6.0 "Enhanced Incremental Backup"- what it really means - HP UX

This is a discussion on Data Protector 6.0 "Enhanced Incremental Backup"- what it really means - HP UX ; Hi, I had posted some suspect on the implementation and performance of Data Protector 6.0's enhanced incremental backup. In the meantime Data Protector was unable to backup the /var directory of some non-Cell-Server client, because backup was terribly slow. At ...

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Thread: Data Protector 6.0 "Enhanced Incremental Backup"- what it really means

  1. Data Protector 6.0 "Enhanced Incremental Backup"- what it really means

    Hi,

    I had posted some suspect on the implementation and performance of Data
    Protector 6.0's enhanced incremental backup.

    In the meantime Data Protector was unable to backup the /var directory of some
    non-Cell-Server client, because backup was terribly slow. At the moment there
    ere about 1.5GB to save, and after about 30 minutes the completion was at
    about "9%". So I had a look at /var:

    /var is mirrored on two SCSI LVD 15kRPM local disks, so it shouldn't be that
    slow. STM found no problems with the disk hardware either. The mirror is OK
    also.

    So some statistics:
    /var/opt/omni/enhincrdb (and its subdirectories) contains about 229 thousand
    files, making 1.76GB!

    So it probably means that when marketing talks about "Enhanced" it actually
    means "huge additional resources required".

    I still don't know why the "Database" used for backup is located on the
    client, and why it isn't a database (like a Berkeley-DB hash) but a collection
    of hundred thousand tiny files instead. Except MS-DOS 3.30 FAT filesystem,
    there's probably nothing in the world with a poorer performance that that!

    So the probably solution is: Disable "enhanced incremental backup" as long as
    it's crap like that (probably will be either until DP 7.0, or forever), and
    also remove those /var/opt/omni/enhincrdb directories wherever you find them
    to restore performance of your system.

    BTW: A similar thing is true for Linux (lot of tiny files are created), but
    the OS can deal much better with that as HP-UX 11.11 it seems (using
    ReiserFS).

    Regards,
    Ulrich

  2. Re: Data Protector 6.0 "Enhanced Incremental Backup"- what it reallymeans

    Ulrich Windl wrote:


    >
    > So the probably solution is: Disable "enhanced incremental backup" as long as
    >



    Out of curiosity: why did you enable it in the first place?

    Regards,
    Frank.

  3. Re: Data Protector 6.0 "Enhanced Incremental Backup"- what it really means

    "Frank Giessler" wrote in message
    news:fj3qpi$s1q$1@lc03.rz.uni-jena.de...
    > Ulrich Windl wrote:
    >
    >
    >>
    >> So the probably solution is: Disable "enhanced incremental backup" as
    >> long as
    > >

    >
    >
    > Out of curiosity: why did you enable it in the first place?
    >


    That's a good question with hindsight, like "Why did I get sooo drunk at the
    work Xmas party?", but it seemed like a good idea at the time.

    I thought the only new "feature" in DP6.0 (from DP5.5) was the "enhanced
    incremental backup" stuff? If it is BAD (Broken As Designed) what's the
    point of upgrading?

    I'm gong to give Ulrich the benefit of the doubt and assume he did this in a
    "test environment" to investigate if/how the feature works. I'll admit to
    trying it also, and coming to much the same conclusion as Ulrich.



    --
    Posted via a free Usenet account from http://www.teranews.com


  4. Re: Data Protector 6.0 "Enhanced Incremental Backup"- what it reallymeans

    Kilgaard wrote:
    > "Frank Giessler" wrote in message
    > news:fj3qpi$s1q$1@lc03.rz.uni-jena.de...
    >> Ulrich Windl wrote:
    >>
    >>
    >>> So the probably solution is: Disable "enhanced incremental backup" as
    >>> long as
    >>>

    >>
    >>
    >> Out of curiosity: why did you enable it in the first place?
    >>

    >
    > That's a good question with hindsight, like "Why did I get sooo drunk at the
    > work Xmas party?", but it seemed like a good idea at the time.
    >
    > I thought the only new "feature" in DP6.0 (from DP5.5) was the "enhanced
    > incremental backup" stuff? If it is BAD (Broken As Designed) what's the
    > point of upgrading?
    >
    > I'm gong to give Ulrich the benefit of the doubt and assume he did this in a
    > "test environment" to investigate if/how the feature works. I'll admit to
    > trying it also, and coming to much the same conclusion as Ulrich.
    >
    >
    >

    My question wasn't meant as criticism. We also use DP6 and the "enhanced
    incremental backup" option is enabled because otherwise files with a
    creation time before the last incremental backup (and then moved around)
    would be backed up in the next full session only. But according to the
    documentation, shouldn't "do not preserve access time attributes" have
    the same effect on UNIX? I hesitate to try because in case of failure I
    would have to switch back to "enhanced", which will very likely lead to
    yet another additional full backup.

    Best regards,
    Frank.

  5. Re: Data Protector 6.0 "Enhanced Incremental Backup"- what it really means

    Frank Giessler writes:

    > Ulrich Windl wrote:
    >
    >
    >>
    >> So the probably solution is: Disable "enhanced incremental backup" as long as
    >>

    >
    >
    > Out of curiosity: why did you enable it in the first place?


    Excellent question!: The idea was to _speed up_ backups by avoiding to save
    identical files multiple times (e.g. if you backup 15 servers having the same
    OS). But it seems the mechanism doesn't work across hosts anyway.

    The other reason was to use synthetic backup or object consolidation, but file
    library code isn't stable also, so I'm fighting with HP support on the problem
    how to delete a file library for about three months. The latest procedure
    would be to dump the database into text files, edit those files, and then
    rebuild the database from those files. You get the idea what's wrong...

    Anyway: When turning _off_ Enhanced Incremental backup on one server, the backup
    time went from 1 hour 30 minutes down to 15 minutes.

    With very few exceptions: If you want something well-done, do it yourself!

    Regards,
    Ulrich

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