| From: | "Jeffrey W(dot) Baker" <jwbaker(at)acm(dot)org> |
|---|---|
| To: | Ulrich Wisser <ulrich(dot)wisser(at)relevanttraffic(dot)se> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Need for speed |
| Date: | 2005-08-17 16:49:37 |
| Message-ID: | 1124297377.423.2.camel@noodles |
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| Thread: | |
| Lists: | pgsql-performance |
On Wed, 2005-08-17 at 11:15 +0200, Ulrich Wisser wrote:
> Hello,
>
> thanks for all your suggestions.
>
> I can see that the Linux system is 90% waiting for disc io. At that time
> all my queries are *very* slow. My scsi raid controller and disc are
> already the fastest available.
What RAID controller? Initially you said you have only 2 disks, and
since you have your xlog on a separate spindle, I assume you have 1 disk
for the xlog and 1 for the data. Even so, if you have a RAID, I'm going
to further assume you are using RAID 1, since no sane person would use
RAID 0. In those cases you are getting the performance of a single
disk, which is never going to be very impressive. You need a RAID.
Please be more precise when describing your system to this list.
-jwb
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