Re: Oracle in an AIX LPAR
- From: Stefan Koehler <contact@xxxxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>, john40855@xxxxxxxxx
- Date: Wed, 4 Mar 2015 16:49:38 +0100 (CET)
Hi John,
>> we see that Oracle appears to be using only 1 thread per CPU almost all the
>> time.
You mean one vCPU = one thread, right? The CPU usage can also be shown as 50%,
but it is not 50% in reality - it depends on the used entitlement per
vCPU.
Is this a dedicated LPAR or a shared (CPU) pool one? If the latter, is it
uncapped (?), what is the max entitlement (?), how many vCPUs (?), what is
the weight-factor (?), what is the SMT factor(?) ?
The tools nmon and topas are lying sometimes - especially in case of vCPUs and
the used entitlement. However you can use nmon (resource option -
shortcut r) to get some of the LPAR setting details. In case of micro
partitioning i would go for lparstat & mpstat.
Best Regards
Stefan Koehler
Freelance Oracle performance consultant and researcher
Homepage: http://www.soocs.de
Twitter: @OracleSK
> John Smith <john40855@xxxxxxxxx> hat am 4. März 2015 um 15:32 geschrieben:
>
> Hi. We do not have a lot of experience running Oracle on AIX, but we
> recently became responsible for an Oracle database in an I series LPAR.
>
> We see that the partition is consistently running at over 50% cpu usage, but
> according to OEM the actual Oracle percentage of that is only about 20
> %.
>
> Also, when we look at the thread usage in NMON and TOPAS, we see that Oracle
> appears to be using only 1 thread per CPU almost all the time. There
> are a very few occasions when additional threads are used, but the usage
> outside the primary thread is very small. We have verified that SMT is
> enabled.
>
> This is oracle 11.2.0.4 on AIX 6.1 Is anyone familiar enough with Oracle on
> AIX to give us an idea on what to look at? Or is this normal behavior?
>
> Thanks for any help you can provide.
>
--
//www.freelists.org/webpage/oracle-l
Other related posts:
