Re: Ideal disk setup for Postgresql 7.4?

>FWIW, 7.4.6 is a binary, drop-in place upgrade for 7.4.2. And 7.4.2 has known
>bugs. However, I understand your situation.
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As soon as we get the go-ahead, I will upgrade. I think the company is
actually looking towards 8.0 certification.

>>Okay, thanks. Even with 7-disks? I trust that.
>>
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>Well, it's less bad with 7 disks than it is with 3, certainly. However,there
>is an obvious and quick gain to be had by splitting off the WAL logs onto
>their own disk resource ... up to 14%+ performance in some applications.
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Pardon my ignorance, but the WAL logs are comprised of pg_xlog and
pg_clog? Their own disk resource, but not within the same channel of
disks the database is on, right?

>>So, RAID 1+0 (sw) is
>>probably the best option. I've run sw RAID personally for years without
>>issue. I am a bit hesitant in doing sw RAID for a production server for
>>a database --- probably because its not my server. Any thoughts on sw
>>RAID for Postgresql?
>>
>>
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>Yes. See my article for one. In generaly, SW RAID on BSD or Linux works
>well for PostgreSQL ... UNLESS your machine is already CPU-bound, in which
>case it's a bad idea. If you're hitting the CS bug, it's definitely a bad
>idea, because the SW RAID will increase context switching.
>
>So if your choice, on your system, is between sw RAID 10, and hw RAID 5, and
>you're having excessive CSes, I'd stick with the HW RAID.
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Okay. InCPU-bound servers, use hw RAID. Any hw raids to avoid?

>>Okay. Darn. While I don't write the queries for the application, I do
>>interact with the company frequently. Their considering moving the
>>queries into the database with PL/pgSQL. Currently their queries are
>>done through ProvIV development using ODBC. Will context switching be
>>minimized here by using PL/pgSQL?
>>
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>Won't make a difference, actually. Should improve performance in other ways,
>though, by reducing round-trip time on procedures. Feel free to recommend
>the company to this list.
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I think their too busy to monitor/watch this list. Not a put-down to
them, but I have to do my own leg work to help decide what we're going
to do.

>>Dual Xeon 2.8 CPUs with HT turned off.
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>Yeah, thought it was a Xeon.
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If we went with a single CPU, like Athlon/Opertron64, would CS
storming go away?

Thanks.

Steve Poe