Re: Peformance Tuning Opterons/ Hard Disk Layout

Is there a real limit for max_connections? Here we've an Oracle server with
up to 1200 simultaneous conections over it!

"max_connections: exactly like previous versions, this needs to be set to
the actual number of simultaneous connections you expect to need. High
settings will require more shared memory (shared_buffers). As the
per-connection overhead, both from PostgreSQL and the host OS, can be quite
high, it's important to use connection pooling if you need to service a
large number of users. For example, 150 active connections on a medium-end
32-bit Linux server will consume significant system resources, and 600 is
about the limit."

C ya,
Bruno

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Michael Adler
Sent: Wednesday, February 23, 2005 3:04 PM
To: John Allgood
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Peformance Tuning Opterons/ Hard Disk Layout

On Wed, Feb 23, 2005 at 11:39:27AM -0500, John Allgood wrote:
> Hello All
>
> I am setting up a hardware clustering solution. My hardware is Dual
> Opteron 550 with 8GB ram. My external storage is a Kingston Fibre
> channel Infostation. With 14 15000'k 36GB drives. The OS we are running
> is Redhat ES 3.0. Clustering using Redhat Cluster Suite. Postgres
> Version is Postgres 7.4.7. We will be setting up about 9 databases which
> range in size from 100MB to 2.5GB on the config. The postgres
> application is mostly read intensive. What would be the best way to
> setup the hardrives on this server. Currently I have it partioned with 2
> seperate raid 5 with 1 failover per raid. I have two database clusters
> configured with a seperate postmaster running for each. Running two
> postmasters seems like a pain but that is the only way I knew to
> seperate the load. I am mostly concerned about disk IO and performance.
> Is my current setup a good way to accomplish the best performance or
> would it be better to use all the drives in one huge raid five with a
> couple of failovers. I have looked around in the archives and found some
> info but I would like to here about some of the configs other people are
> running and how they have them setup.

http://www.powerpostgresql.com/PerfList/

Consider a separate array for pg_xlog.

With tablespaces in 8.0, you can isolate much of the IO in a single
cluster.

-Mike Adler

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