Re: Need suggestions on kernel settings for dedicated FreeBSD/Postgresql machine

On Fri, Aug 7, 2009 at 5:24 PM, Culley Harrelson<harrelson(at)gmail(dot)com> wrote:
> Hi Everyone,
>
> I manage a freeBSD server that is dedicated to postgresql.  The
> machine has 4 gigs of ram and there is a single database powering a
> web application that is hosted on a neighboring machine.  The web
> application is mostly reading the database but there are considerable
> writes and I don't want to tune the machine exclusively for writes.  I
> realize more information would be needed to optimally tune the machine
> but I am seeking advice on making some sane kernel settings for a
> general purpose database on a dedicated system.  Currently I have:
>
> $ cat /etc/sysctl.conf
>
> kern.ipc.shmmax=268435456
> kern.ipc.shmall=65536
>
> and
>
> $ cat /boot/loader.conf
> kern.ipc.semmni="256"
> kern.ipc.semmns="512"
> kern.ipc.semmnu="256"
>
> In postgresql.conf I have:
>
> max_connections = 180
> shared_buffers = 28MB
>
> I would like to increase this to 256 connections and make sure the
> kernel settings are giving postgresql enough breathing room without.
> I suspect my settings are conservative and since the machine is
> dedicated to postgresql I would like to give it more resources if they
> could be used.  Any suggestions?

This might be worth a look, for starters.

http://pgfoundry.org/projects/pgtune/

...Robert