Re: Dual Xeon + HW RAID question - Mailing list pgsql-performance

From SZUCS Gábor
Subject Re: Dual Xeon + HW RAID question
Date
Msg-id 00b901c34f49$1ed04b40$0403a8c0@fejleszt4
Whole thread Raw
In response to Re: Dual Xeon + HW RAID question  ("Nikolaus Dilger" <nikolaus@dilger.cc>)
Responses Re: Dual Xeon + HW RAID question
Re: Dual Xeon + HW RAID question
List pgsql-performance
Alexandre,

I missed your orig. post, but AFAIK multiprocessing kernels will handle HT
CPUs as 2 CPUs each. Thus, our dual Xeon 2.4 is recognized as 4 Xeon 2.4
CPUs.

This way, I don't think HT would improve any single query (afaik no postgres
process uses more than one cpu), but overall multi-query performance has to
improve.

----- Original Message -----
From: "Nikolaus Dilger" <nikolaus@dilger.cc>
Sent: Saturday, July 12, 2003 8:25 PM


Alexandre,

Since you want the fastest speed I would do the 2 data
disks in RAID 0 (striping) not RAID 1 (mirroring).

If you would care about not loosing any transactions
you would keep all 3 disks in RAID 5.

Don't know the answer to the Hyperthreading question.
Why don't you run a test to find out?

Regards,
Nikolaus

On Thu, 10 Jul 2003 14:43:25 -0300 (BRT), "alexandre
arruda paes :: aldeia digital" wrote:

>
> Hi,
>
> I have this machine with a 10 million records:
> * Dual Xeon 2.0 (HyperThreading enabled), 3 7200 SCSI
,
> Adaptec 2110S,
> RAID 5 - 32k chunk size, 1 GB Ram DDR 266 ECC, RH 8.0
-
> 2.4.18
>
> The database is mirrored with contrib/dbmirror in a P4
> 1 Gb Ram + IDE
>
> If a disk failure occurs, I can use the server in the
> mirror.
>
> I will format the main server in this weekend and I
> have seen in the list
> some people that recomends a Software RAID instead HW.
>
> I think too remove the RAID 5 and turn a RAID 1 for
> data in 2 HDs.
> SO, WAL and swap in the thrid HD.
>
> My questions:
>
> 1) I will see best disk performance changing the disk
> layout like above
> 2) HyperThreading really improve a procces basead
> program, like postgres
>
> Thank´s for all
>
> Alexandre


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