Re: Oracle in an AIX LPAR

>> 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: _at_OracleSK   

> John Smith <john40855_at_gmail.com> 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.
>

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