Re: Dual Xeon + HW RAID question

SZUCS,

In my tests, I don´t a great performance enhacement with HT.

I suspect that my problem resides on I/O performance. I will
wait for a best moment to resinstall the system with other
disk configurations and then I will report here.

Thanks for all replys!

Alexandre

> 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(at)dilger(dot)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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