Re: Do we have to disable NUMA to configure HugePages?
- From: Rajesh Aialavajjala <r.aialavajjala@xxxxxxxxx>
- To: fmh <fmhabash@xxxxxxxxx>
- Date: Mon, 14 Oct 2013 11:35:02 -0400
Unless I am mistaken - given that NUMA is disabled in the RDBMS starting
with 11.2 - there should be no explicit requirement to perform any
disabling - depending on your OS - you may have NUMA enabled at the OS
level but the database should (I'd think) not take that - you'll notice
from 1484809.1 that the combination of the OS and the fact that NUMA is
enabled by default is what led to an issue.
Vide 759565.1 - Oracle states "When running an Oracle database with NUMA
support in a NUMA capable environment, Oracle will by default detect if the
hardware and operating system are NUMA capable and enable Oracle NUMA
support." - this might imply that if you are running 11.2 on NUMA capable
h/w - you will need to validate if NUMA is being enabled. All the bugs
listed in this note however were fixed as of Release 11.2.0.2
It would appear that there's no incompatibility when running huge pages on
a NUMA system - given that the alert log in such a situation has been known
to report
Numa pool size adjusted****************** Huge Pages Information
*****************
Huge Pages memory pool detected (total: 10395 free: 7995)
DFLT Huge Pages allocation successful (allocated: 146)
NUMA Huge Pages allocation on node (1) (allocated: 186)
NUMA Huge Pages allocation on node (0) (allocated: 182)
DFLT Huge Pages allocation successful (allocated: 1)
indicating the use of NUMA and Huge Pages...
References:
http://blog.yannickjaquier.com/hpux/non-uniform-memory-access-numa-architecture-with-oracle-database-by-examples.html
The official response should come from Oracle though -- perhaps best to log
an SR and request their input - and this might be something you've already
done.
Lastly - excellent reading from the comments in
http://kevinclosson.wordpress.com/2010/03/18/you-buy-a-numa-system-oracle-says-disable-numa-what-gives-part-i/
Thanks,
--Rajesh
On Fri, Oct 11, 2013 at 2:16 PM, fmh <fmhabash@xxxxxxxxx> wrote:
> Thanks Raj.
>
> I had missed 864633.1. I reviewed ...
> Instance Crashed with Linux-x86_64 Error: 14: Bad address after Hugepages
> is Enabled on SUSE Linux (Doc ID 1484809.1)
> Oracle Not Utilizing Hugepages (Doc ID 803238.1)
> Both ask to disable NUMA in 10.2.0.7 & 11.1.0.7.
>
> Unless I'm missing it, the question remains, is numa & HPs incompatible?
> If yes, is it enough to disable numa at DB level or do we have to disable
> it at the OS/HW level?
> Have you seen a clear statement on this? I have not.
>
>
>
> On Fri, Oct 11, 2013 at 12:24 PM, Rajesh Aialavajjala <
> r.aialavajjala@xxxxxxxxx> wrote:
>
>> If I'm not mistaken - NUMA was disabled by default starting w/ 11.2
>>
>> Refer Enable Oracle NUMA support with Oracle Server Version 11.2.0.1
>> (Doc ID 864633.1) which states "Starting with 11.2.0.1, Oracle NUMA
>> support is disabled by default."
>>
>> Also - USE_LARGE_PAGES To Enable HugePages (Doc ID 1392497.1)
>>
>> I believe that starting w/ 11.2 you had to use the "_enable_NUMA_support"
>> parameter to allow / enable this feature.
>>
>> Also --
>>
>> http://martincarstenbach.wordpress.com/2012/04/27/little-things-i-didnt-know-difference-between-_enable_numa_support-and-numactl/
>>
>> http://kevinclosson.wordpress.com/2010/03/18/you-buy-a-numa-system-oracle-says-disable-numa-what-gives-part-i/
>>
>> http://kevinclosson.wordpress.com/2009/05/14/you-buy-a-numa-system-oracle-says-disable-numa-what-gives-part-ii/
>>
>> http://kevinclosson.wordpress.com/2010/03/31/you-buy-a-numa-system-oracle-says-disable-numa-what-gives-part-iii/
>>
>> Thanks,
>>
>> --Rajesh
>>
>>
>> On Fri, Oct 11, 2013 at 12:12 PM, fmh <fmhabash@xxxxxxxxx> wrote:
>>
>>> I have seen references in MOS docs (Doc ID 1484809.1) & (803238.1) to
>>> disable NUMA before configuring HPs. They were specific to 10g and 11.1.
>>> Is this required for 11.2 (or may be at all)? Can't locate a clear cut
>>> answer.
>>>
>>> --
>>>
>>> ----------------------------------------
>>> Thank you.
>>>
>>>
>>> --
>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>>
>>
>
>
> --
>
> ----------------------------------------
> Thank you.
>
>
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