On Fri, 2004-07-30 at 19:22, Christopher Browne wrote:
> After a long battle with technology, stephane.tessier@abovesecurity.com ("Stephane Tessier"), an earthling, wrote:
> > I think with your help guys I'll do it!
> >
> > I'm working on it!
> >
> > I'll work on theses issues:
> >
> > we have space for more ram(we use 2 gigs on possibility of 3 gigs)
>
> That _may_ help; not completely clear.
>
> > iowait is very high 98% --> look like postgresql wait for io access
>
> In that case, if you haven't got a RAID controller with battery backed
> cache, then that should buy you a BIG boost in performance. Maybe
> $1500 USD; that could be money FABULOUSLY well spent.
>
> > raid5 -->raid0 if i'm right raid5 use 4 writes(parity,data, etc) for each
> > write on disk
>
> I try to avoid talking about RAID levels, and leave them to others
> :-).
FYI, in a previous post on this topic, the original poster put up a top
output that showed the machine using 2 gigs of swap with 150 Meg for
kernel cache, and all the memory being used by a few postgresql
processes. The machine was simply configured to give WAY too much
memory to shared buffers and sort mem and this was likely causing the
big slowdown.
Adding a battery backed caching RAID controller and properly configuring
postgresql.conf should get him into the realm of reasonable performance.