Re: Ubutu 12.04 and PostgreSQL9.2.1

Hi,

On 7 December 2012 14:17, ac@hsk.hk <ac@hsk.hk> wrote:
> I have questions about Linux Write cache sizing:
>
> 1) /proc/sys/vm/dirty_ratio : current value (default)  20
> 2) /proc/sys/vm/dirty_background_ratio: current value (default)  10
>
> I am using Ubuntu 12.04 (8GB RAM) and PostgreSQL 9.2.1, what values of these kernel ratios
> should be set for better PostgreSQL database performance?

Read this thread:
http://archives.postgresql.org/pgsql-performance/2011-10/msg00076.php
Mainly,
- http://archives.postgresql.org/pgsql-performance/2011-10/msg00078.php
- and http://archives.postgresql.org/pgsql-performance/2011-10/msg00080.php

To sum up:
- with 8G RAM you should be fine with the defaults
- keep keep dirty_ratio lower than the size of your disk controller cache
- you can use dirty_bytes and dirty_background_bytes in recent kernels

--
Ondrej Ivanic
(http://www.linkedin.com/in/ondrejivanic)