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11.31 pseudo swap

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Ivan Ferreira
Honored Contributor

11.31 pseudo swap

Hi all.

During a load test one of our database servers, the process died with the following message in the syslog file:

vmunix: Deferred swap reservation failure pid:

After searching, I saw that pseudo swap should always be used in this version of HP-UX.

What I don't understand is why keeps incrementing the reserved space.

In Tru64, this was controlled by a kernel parameter, as was before with the swapmem_on kernel parameter.

No other applications are running on this server besides the Oracle Database.

This means that I need a lot more of swap than my RAM, and now we are about to install new servers with 256 GB of RAM.

Attached is the memory usage during test with a load that the server was able to handle. But increasing the load (the number of test users), the swap reservation failure message appears again.

Is this normal or there is something that should enabled/tuned at the Oracle database?
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
4 REPLIES
Johnson Punniyalingam
Honored Contributor

Re: 11.31 pseudo swap

Hi Ivan,

Can please check below thread. simliar to your problem

http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1252835136279+28353475&threadId=364811

Current Swap as per your attachmnet output:-

8*3 = 24GB.

As per my understanding heard from some of my mentors advice to have swap sapce double the size of your psyical memory ? best pratice.

HTH,

Cheers,
Johnson




Problems are common to all, but attitude makes the difference
Hakki Aydin Ucar
Honored Contributor
Dennis Handly
Acclaimed Contributor
Solution

Re: 11.31 pseudo swap

>I saw that pseudo swap should always be used in this version of HP-UX.

Not "should" but "is".

>This means that I need a lot more of swap than my RAM, and now we are about to install new servers with 256 GB of RAM.

You either need more swap or RAM. You need enough total swap to match your Oracle requirements.

>Is this normal or there is something that should enabled/tuned at the Oracle database?

Yes to both. Until you get more swap, you need to tell Oracle to use less memory.
Hein van den Heuvel
Honored Contributor

Re: 11.31 pseudo swap

Hello Ivan.

This all seemed much easier in Tru64 didn't it?
There 'lazy' swap was just great, and we ran our benchmarks on hefty (many-GB) machines, with just 2 or 4 GB swap just in case we did not predict the usage correctly.

There was a recent topic on this, but it did not have a clear outcome at the time of this reply. There are some interesting reference in there though.

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1367439

hth,
Hein.