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Former Member

Backup performance: AIX 6.1 Oracle 11.2 filesystemio_options

Dear colleagues,

after switching the filesystemio_options from ASYNCH to SETALL the backup performance decreased by 20%.

In the past we had /oracle/<SID> and /oracle/<SID>/sapdata in one filesystem and thought this might prevent Oracle from the benefits of O_CIOR.

So we redesigned the filesystem and put /oracle/<SID>/sapata in an extra filessytem. Unfortunately the backup performance is still decreased when using SETALL.

Could it be related to the fact that we don't use local disks but SAN-disks?

It is quite annoying that we don't get the best performance when following the SAP, Oracle and IBM recommendations.

Best regards, Henning

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Additional information:

- Mount-option cio is not set as recommended.

- We don't suffer functional problems. "Only" the performance is decreased.

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2 Answers

  • Best Answer
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    Former Member
    Jun 17, 2013 at 01:09 PM

    Another additional information:

    We are backing up to TSM via backint. No direct attached tapes or disks for backup.

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    • Former Member Former Member

      Hi all,

      to complete the information. The parameter memoryefficientbackup=yes didn't show any measurable performance improvement on two systems. Therefore I disabled it again.

      Best regards, Henning

  • Jun 17, 2013 at 01:08 PM

    Hi Henning,

    > It is quite annoying that we don't get the best performance when following the SAP, Oracle and IBM recommendations.

    All of these "best practices" are a good rule of thumb, but nothing more. Luckily every client environment is different and that's how i earn my money. Showing my clients how it really works under the hood and how to improve it 😉

    > So we redesigned the filesystem and put /oracle/<SID>/sapata in an extra filessytem.

    That's was the first right step.

    > Unfortunately the backup performance is still decreased when using SETALL. Could it be related to the fact that we don't use local disks but SAN-disks?

    Well at first you need to know, that setting filesystemio_options to "SETALL" does implicit CIO (for the Oracle processes) even if the file system is not mounted with "cio" option. Check my blog for more details. SAN disks usually scale pretty well (even better as local ones), but it depends on the used storage device (like SVC, DS or XIV) if they are setup right (on OS and behind).

    The second question is how do you perform backup? Do you use RMAN or "old fashion flat file"? What is the bottleneck (reading, transferring or sending the data)? Do you use a third party product like TDP for mySAP or TDP for Oracle?

    For example - there should be no CIO problem when using using Oracle 11.2.0.2 (or higher) on AIX 6.1 wit TDP for mySAP (and "old fashion backup"), otherwise you maybe need to adjust the third party buffers to get a pretty good throughput.

    As always .. too less information and  it depends 😉

    Regards

    Stefan

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