Message-ID: <4909CF9C.80701@technocon.com>
Date: Thu, 30 Oct 2008 16:15:40 +0100
From: Christiaan Willemsen <cwillemsen@technocon.com>
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To: pgsql-performance@postgresql.org
Subject: Configuring for maximum memory usage
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Hi there,

I configured OpenSolaris on our OpenSolaris Machine. Specs:

2x Quad 2.6 Ghz Xeon
64 GB of memory
16x 15k5 SAS

The filesystem is configured using ZFS, and I think I have found a 
configuration that performs fairly well.

I installed the standard PostgreSQL that came with the OpenSolaris disk 
(8.3), and later added support for PostGIS. All fime.
I also tried to tune postgresql.conf to maximize performance and also 
memory usage.

Since PostgreSQL is the only thing running on this machine, we want it 
to take full advantage of the hardware. For the ZFS cache, we have 8 GB 
reserved. The rest can be used by postgres.

The problem is getting it to use that much. At the moment, it only uses 
almost 9 GB, so by far not enough. The problem is getting it to use 
more... I hope you can help me with working config.

Here are the parameters I set in the config file:

shared_buffers = 8192MB
work_mem = 128MB
maintenance_work_mem = 2048MB
max_fsm_pages = 204800
max_fsm_relations = 2000

Database is about 250 GB in size, so we really need to have as much data 
as possible in memory.

I hope you can help us tweak a few parameters to make sure all memory 
will be used.