Re: 'postmaster -B [nBuffers]' - Mailing list pgsql-admin

From Chris Albertson
Subject Re: 'postmaster -B [nBuffers]'
Date
Msg-id 38F79FB8.65CC745@jps.net
Whole thread Raw
In response to 'postmaster -B [nBuffers]'  (Jack Zhu <jzhu@netcom-sys.com>)
List pgsql-admin
Jack Zhu wrote:
>
> The default for disk buffers number is 64. I think it's not big enough.
> If my box has 128 or 256 MB RAM, what's the percentage of RAM should be
> assigned to postmaster by using '-B' option? Any experience about the
> performence regarding to the change of buffer size?


Try this:  Run the "top" display and watch the CPU utilization.
Add buffers and/or more physical RAM untill your Postgresql
server becomes CPU bound.  You can tell if it is when the
utilization is close to 100%.  If the CPU utilization is low
it means the CPU is waiting on the disk.

A direct answer is "B = a few thousand"

   --Chris Albertson             home: chrisja@jps.net
     Redondo Beach, California   work: calbertson@logicon.com

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