Disable Transparent Hugepages on SLES11, RHEL6, RHEL7, OL6, OL7 and UEK2 Kernels

This blog post is not related to database upgrades and migrations. But still I think it is very useful for many customers operating on modern Linux systems.

Recommendation 

Support just published an ALERT strongly recommending to disable Transparent Hugepages on Linux systems. And the below information does not apply to RAC systems only but also to single instance environments.

Which Linux Distrubutions/Kernels are affected? 

  • SLES11
  • RHEL6 and RHEL7
  • OL6 and OL7
  • UEK2 Kernels

What are the Issues? 

I’m quoting MOS Note: 1557478.1 (ALERT: Disable Transparent HugePages on SLES11, RHEL6, RHEL7, OL6, OL7 and UEK2 Kernels):

Because Transparent HugePages are known to cause unexpected node reboots and performance problems with RAC, Oracle strongly advises to disable the use of Transparent HugePages. In addition, Transparent Hugepages may cause problems even in a single-instance database environment with unexpected performance problems or delays. As such, Oracle recommends disabling Transparent HugePages on all Database servers running Oracle.

This ONLY applies to the new feature Transparent HugePages, Oracle highly recommends the use of standard HugePages that were recommended for previous releases of Linux.  See MOS Note:361323.1 for additional information on HugePages. 

As far as I see you’ll have to reboot the server in order to disable Transparent Hugepages – the default is usually ALWAYS.

More Information?

–Mike

3 thoughts on “Disable Transparent Hugepages on SLES11, RHEL6, RHEL7, OL6, OL7 and UEK2 Kernels

  1. Hi,
    I’ts strange the publication date is very recent but it seems it was already publish in the past.
    I used that specific note to install Linux for a Production environment last year.

    Regards,

    Nicolas

  2. Nicolas,

    thanks – I wasn’t aware of it and it is still not part of the alerts mentioned in: 1683799.1. Not even 1587357.1 has it mentioned 🙁

    Cheers
    Mike

  3. Yes, it’s still not mentioned in the pre-requisites or in the patchset know issues.

    I tried to configure a search to find published Alert in M.O.S about databases but I haven’t found a nice way.

    It could be good to have a fixed note in M.O.S to summarize the published Alerts. A note like 1565065.1 would probably be a nice place to link the alerts about 12c for example.

    Regards,
    Nicolas

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