Re: [squid-users] High cpu load with squid

From: Michał Prokopiuk <>
Date: Thu, 18 Nov 2010 12:47:33 +0100

Dnia Czwartek, 18.11.2010 o 11:18 Amos Jeffries napisał:

> Okay. The obvious config reasons for slowness are gone. So the next
> thing is to find out exactly what Squid is doing.
> * you can check with strace to see whats the thing taking out the CPU.

Not possible, when I run strace load groving wery fast, and i can't do anything.

> Has the box started using swap memory space now? That can drastically
> slow downs Squids index lookups or buffering of information relayed.

No, on server are about 2 gb free ram (cached).

> Is RAID still running trying to duplicate the random cache IO actions?

No, i remove raid, and create two cache_dir:

cache_dir aufs /var/spool/squid-cache/cache 10000 60 100
cache_dir aufs /var/spool/squid-cache/sda6/cache 10000 60 100

> Have you noticed if the problem appears and lasts for around 2 hours,
> then goes away? that would indicate your DNS TTL overrides forcing squid
> to try the wrong IPs for some site. CDN hosted sites (eg akamai and
> youtube) can change their IPs with no notice when there are routing
> problems to work around.

The problem appears about 30 min - 1 h. I have local dnscache.

I have one new information - when i decrease maximum_object_size from 100M to 20 M, squid work for two days without any problem, and then squid again get a lot of cpu. With 100M maximum_object_size squit work stable only for first fiew hours.

Michał Prokopiuk
Received on Thu Nov 18 2010 - 11:47:42 MST

This archive was generated by hypermail 2.2.0 : Thu Nov 18 2010 - 12:00:03 MST