Re: shared_buffers advice

On Thu, Mar 11, 2010 at 5:19 PM, Paul McGarry <paul@paulmcgarry.com> wrote:
> On 11 March 2010 16:16, Ben Chobot <bench@silentmedia.com> wrote:
>
>> I *can* say a 10GB shared_buffer value is working "well" with my 128GB of RAM..... whether or not it's "optimal," I
couldn'tsay without a lot of experimentation I can't afford to do right now. You might have a look at the
pg_buffercachecontrib module. It can tell you how utilized your shared buffers are. 
>
> Thanks Ben and Greg,
>
> I shall start with something relatively sane (such as 10GB) and then
> see how we go from there.
>
> Once this server has brought online and bedded in I will be updating
> our other three servers which are identical in hardware spec and all
> have the same replicated data so I'll be able to do some real world
> tests with different settings withn the same load.
>
> (Currently one is currently running postgresql 8.1 on 32bit OS under a
> VM, the other two running 8.3 on 64bit OS with 64gig of memory but
> with Postgres still tuned for the 8 gigs the servers originally had
> and under a VM).

Definitely look at lowering the swappiness setting.  On a db server I
go for a swappiness of 1