LVM, JFS2 tuning questions on AIX 5.3 - Aix

This is a discussion on LVM, JFS2 tuning questions on AIX 5.3 - Aix ; Hello, I'm trying to come up to speed on storage management on AIX 5.3, specifically file system configuration, and have some questions. I'll be allocating all volumes except the rootvg on a LeftHand iSCSI SAN, spread across many physical drives. ...

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Thread: LVM, JFS2 tuning questions on AIX 5.3

  1. LVM, JFS2 tuning questions on AIX 5.3

    Hello,

    I'm trying to come up to speed on storage management on AIX 5.3,
    specifically file system configuration, and have some questions. I'll
    be allocating all volumes except the rootvg on a LeftHand iSCSI SAN,
    spread across many physical drives. The main workload is an Oracle
    database server, with some local SQL batches.

    Q1) I get the impression that physical partition size and volume group
    type (regular, big, scalable) is mainly about overall size
    constraints. So I should estimate how large the volumes and volume
    group could be expected to ever grow, and choose accordingly. Tuning
    for many small files vs. few big files is pretty much orthogonal to pp
    size and vg type. Is that correct?

    Q2) On the other hand, when creating jfs2 file systems, you can tune
    for many small files by by choosing a smaller value for agblksize.
    Correct?

    Q3) I will have a mix of file systems, some with many small, and some
    with few large files. Is it likely to be worth the effort to tune for
    this? Can I expect a performance payoff? Or is the payoff only in
    reducing wasted space?

    Q4) What are the tradeoffs on inline jfs2 logs vs. external logs?

    Q5) How do I decide how big a jfs2 log I need?


  2. Re: LVM, JFS2 tuning questions on AIX 5.3

    On Oct 11, 7:03 pm, phr wrote:
    > Hello,
    >
    > I'm trying to come up to speed on storage management on AIX 5.3,
    > specifically file system configuration, and have some questions. I'll
    > be allocating all volumes except the rootvg on a LeftHand iSCSI SAN,
    > spread across many physical drives. The main workload is an Oracle
    > database server, with some local SQL batches.
    >
    > Q1) I get the impression that physical partition size and volume group
    > type (regular, big, scalable) is mainly about overall size
    > constraints. So I should estimate how large the volumes and volume
    > group could be expected to ever grow, and choose accordingly. Tuning
    > for many small files vs. few big files is pretty much orthogonal to pp
    > size and vg type. Is that correct?
    >
    > Q2) On the other hand, when creating jfs2 file systems, you can tune
    > for many small files by by choosing a smaller value for agblksize.
    > Correct?
    >
    > Q3) I will have a mix of file systems, some with many small, and some
    > with few large files. Is it likely to be worth the effort to tune for
    > this? Can I expect a performance payoff? Or is the payoff only in
    > reducing wasted space?
    >
    > Q4) What are the tradeoffs on inline jfs2 logs vs. external logs?
    >
    > Q5) How do I decide how big a jfs2 log I need?


    For Oracle, I would start here, focusing on articles by Dale Martin
    and Damir Rubic

    http://www-03.ibm.com/support/techdo...1000&Expand=13


  3. Re: LVM, JFS2 tuning questions on AIX 5.3

    > For Oracle, I would start here, focusing on articles by Dale Martin
    > and Damir Rubic
    >
    > http://www-03.ibm.com/support/techdo.../WP-ByProduct?...


    Lots of good stuff there. "Configuring IBM System Storage DS4000
    Series for Oracle Database Applications" has great information. Even
    though my LeftHand iSCSI storage is much different, many of the
    concepts apply. Thanks.


  4. Re: LVM, JFS2 tuning questions on AIX 5.3

    If your Oracle database in on RAID 5, don't undersize the segment size. We
    started at an 8KB logical volume segement size on our DS4800 to match Oracle
    blocking and it absolutely killed performance. We ended up redoing all our
    Oracle LV's on logical volumes with a 64K segment size.

    "phr" wrote in message
    news:1192287777.918221.37120@z24g2000prh.googlegro ups.com...
    >> For Oracle, I would start here, focusing on articles by Dale Martin
    >> and Damir Rubic
    >>
    >> http://www-03.ibm.com/support/techdo.../WP-ByProduct?...

    >
    > Lots of good stuff there. "Configuring IBM System Storage DS4000
    > Series for Oracle Database Applications" has great information. Even
    > though my LeftHand iSCSI storage is much different, many of the
    > concepts apply. Thanks.
    >




  5. Re: LVM, JFS2 tuning questions on AIX 5.3

    On Oct 13, 11:02 am, phr wrote:
    > > For Oracle, I would start here, focusing on articles by Dale Martin
    > > and Damir Rubic

    >
    > >http://www-03.ibm.com/support/techdo.../WP-ByProduct?...

    >
    > Lots of good stuff there. "Configuring IBM System Storage DS4000
    > Series for Oracle Database Applications" has great information. Even
    > though my LeftHand iSCSI storage is much different, many of the
    > concepts apply. Thanks.


    Been doing arrays since the I in RAID meant inexpensive vs
    independent.
    (marketing didn't allow that one for very long..... maybe 18 months)

    I would not select RAID 5 for a read/write Oracle DB. Write penalty
    too high.
    If this is a read only DB, I would still select RAID 6 vs RAID 5 for
    the additional
    fault tolerance. Dual distributed parity.

    I like RAID 1/0 for mixed read/write Oracle DB's. (EMC arrays)
    Try a RAID 5 vs 10 in your lab, and let us know your results.

    An old article, but still makes many valid points.

    http://findarticles.com/p/articles/m...23/ai_98709771


    good luck


  6. Re: LVM, JFS2 tuning questions on AIX 5.3

    Now that the I in RAID means independnt and disk subsystems now come with
    large caches, the write penalty of RAID 5 has been greatly reduced.

    wrote in message
    news:1192466640.145974.29200@e9g2000prf.googlegrou ps.com...
    > On Oct 13, 11:02 am, phr wrote:
    >> > For Oracle, I would start here, focusing on articles by Dale Martin
    >> > and Damir Rubic

    >>
    >> >http://www-03.ibm.com/support/techdo.../WP-ByProduct?...

    >>
    >> Lots of good stuff there. "Configuring IBM System Storage DS4000
    >> Series for Oracle Database Applications" has great information. Even
    >> though my LeftHand iSCSI storage is much different, many of the
    >> concepts apply. Thanks.

    >
    > Been doing arrays since the I in RAID meant inexpensive vs
    > independent.
    > (marketing didn't allow that one for very long..... maybe 18 months)
    >
    > I would not select RAID 5 for a read/write Oracle DB. Write penalty
    > too high.
    > If this is a read only DB, I would still select RAID 6 vs RAID 5 for
    > the additional
    > fault tolerance. Dual distributed parity.
    >
    > I like RAID 1/0 for mixed read/write Oracle DB's. (EMC arrays)
    > Try a RAID 5 vs 10 in your lab, and let us know your results.
    >
    > An old article, but still makes many valid points.
    >
    > http://findarticles.com/p/articles/m...23/ai_98709771
    >
    >
    > good luck
    >




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