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Re: Itanium vs PA-Risc for Oracle Databases

 
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Chris Fadrowski
Super Advisor

Itanium vs PA-Risc for Oracle Databases

We recently moved all of our 11 Oracle DB's from a v2500 PA-Risc box running 11.0 hpux to a RX4640 Itanium server running 11.23v2.

we have 16 gb of memory on both boxes, and we did NOT change any SGA's just ftp'd copies of the databases over to the itanium box. However, memory on the Itanium is at 99% and it was less then 60% on the V2500 server.

Can someone tell me if there is a difference on how the Itanium boxes or 11.23v2 allocates memory? I used Oracles documentation for kernel parameters but is there another one i should be looking at?
16 REPLIES 16
Chris Fadrowski
Super Advisor

Re: Itanium vs PA-Risc for Oracle Databases

One more thing,

Buffer Cache is at 8gb on this system. dbc_max_pct is at the default of 50 for it's value
Eric Antunes
Honored Contributor

Re: Itanium vs PA-Risc for Oracle Databases

Hi Chris,

What is the RDBMS version? I'm asking because only Oracle 9.2 64-bit is certified on Itanium 11.23 and you should patch it to 9.2.0.6...

Best Regards,

Eric
Each and every day is a good day to learn.
Chris Fadrowski
Super Advisor

Re: Itanium vs PA-Risc for Oracle Databases

9.2.0.6 Oracle. ONly version 9 runs on itanium. (but i am no DBA)
Eric Antunes
Honored Contributor
Solution

Re: Itanium vs PA-Risc for Oracle Databases

Since Oracle has a buffer cache, you should reduce the OS buffer cache, thus avoiding double caching: your OS buffer cache should be something between 300-400Mb, so reduce dbc_max_pct and dbc_min_pct to, respectively, 3 (3%*16Gb=3/100*16384Mb=492Mb) and 2.

Furthermore, check recomendations for other significant kernel parameters when running Oracle in anexed doc...

Best Regards,

Eric
Each and every day is a good day to learn.
Patrick Wallek
Honored Contributor

Re: Itanium vs PA-Risc for Oracle Databases

The default buffer cache is absolutely ludicrous. Reduce at the first opportunity. On a 16GB system, a max value of between 3 and 5 % should be sufficient. I might consider dbc_min at 3 and dbc_max at 5.
Eric Antunes
Honored Contributor

Re: Itanium vs PA-Risc for Oracle Databases

Hi,

For more kernel parameters (since I'm not able to attach docs. witch more than 1Mb), see this thread:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=915316

Best Regards,

Eric
Each and every day is a good day to learn.
Jean-Luc Oudart
Honored Contributor

Re: Itanium vs PA-Risc for Oracle Databases

Chris

I believe you just hit bug 3890965 "ORACLE CONSUMES LARGER MEMORY IN HP-UX ITANIUM PORT"

Regards
Jean-Luc
fiat lux
Jean-Luc Oudart
Honored Contributor

Re: Itanium vs PA-Risc for Oracle Databases

Hi

You can tune your memory as per other post., but I don't think the "bug" is corrected in 9.2.0.6. Check Metalink (or ask your DBA to do it for you).

From this :
[output of glance] - Itanium - Text RSS/VSS:112mb/112mb Data RSS/VSS:5.0mb/6.0mb Stack RSS/VSS:384kb/256mb Shmem RSS/VSS:229mb/242mb Other RSS/VSS:7.8mb/ 24mb - PA-RISC - Text RSS/VSS: 64mb/ 64mb Data RSS/VSS:2.0mb/2.0mb Stack RSS/VSS:128kb/192kb Shmem RSS/VSS:226mb/242mb Other RSS/VSS:4.4mb/9.0mb .
"Text Segment is about double the size but most of them are shared among each server processes so it is not a problem. . The problem is that Data Segment differs about 4MB. Data Segments are not shared among the server processes so this memory adds up when there are many connections. "

Regards
Jean-Luc

fiat lux

Re: Itanium vs PA-Risc for Oracle Databases

Yup, Oracle on IA64 is one greedy sonovab****. Take a look at the release notes:

http://download-uk.oracle.com/docs/pdf/B10566_05.pdf

Section 6.1, page 21


Also see the discussion here. When I size customers moving from PA-RISC to IA64, I generally add 50% more memory for Oracle systems:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=814468

HTH

Duncan

I am an HPE Employee
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