FW: [ADMIN] Shared_buffers and kernel parameters, tuning

> -----Original Message-----
> From:    Lending, Rune [SMTP:rune.lending@inpoc.com]
> Sent:    05 June 2003 10:11
> To:    'pgsql-admin@postgresql.org'
> Subject:    [ADMIN] Shared_buffers and kernel parameters, tuning
>
> After days of searching and testing I have come up with this way of
> configuring our postgresql 7.2 db.
> I have not yet increased my shared_buffer as high as suggested below on
> our
> prod machine (24-7 high traffic), but after testing on our dev machines
> this allows at least the databse to start up. It is very difficult to test
> the actual performance since there is a hugh difference in traffic on dev
> and prod.
> Here is what we have:
>
> We have a high traffic system with a database described as followed:
>
> 4 pentium 3 633 cpu's
> 3753456 kB RAM (3.5 Gb)
> Red Hat Linux 7.2
> postgresql 7.2
>
>
> What I like to do is:
>
> /proc/sys/kernel/sem=250 32000 100 500 (after advise from forum/docs)
> /proc/sys/kernel/shmmax=1921769472 (RAM / 2 * 1024 - this
> piece of math I got from some of oracle's support pages (ooopps) actually
> )
>
> /proc/sys/kernel/shmall=1921769472 (RAM / 2 * 1024)
>
> in postgresql.conf:
>
> shared_buffers = 117248 (shmmax / 2 / 1024 / 8 ) This I got from this
> forum.
>
>
> Does this sound right or am I totally out of bounds here? I have, as said
> before done this on our dev macine ( a lot smaller machine ), but it would
> be nice with some feedback ..
>
> Thanx in advance for response.
>
> /rune
>
>