Re: Ridiculous load

On 12/9/04 9:23 AM, "Peter Haworth" <pmh(at)edison(dot)ioppublishing(dot)com> wrote:

> It runs RHEL ES v3, kernel 2.4.21-20.ELsmp
> It's generally a very stable box which runs a number of postgresql
> instances. But last night we hit very high low averages - 10+, vs the
> normal 0-2.
> The culprit appeared to be kswapd, which was using huge amounts of cpu.
> I'd like to know why!

There were some major changes in swap management somewhere in the linux 2.4
kernel (also RH 3.0 ES). I don't off hand remember exactly which level.
Under a heavy I/O load, we also saw kswapd going nuts with the 2.4.21
kernel, destroying system performance. The only solution we found was to
upgrade to a 2.6 kernel. The problem has not reoccurred since then. Our
database is currently about 67 gigabytes and is growing at about 1 million
records per day. We are using Postgresql 7.4.x.

Wes