Re: Re: [squid-users] no load on squid box - yet I get squidaio_queue_request CONGESTION

From: Klavs Klavsen <>
Date: Tue, 13 Nov 2001 08:57:36 +0100

see comments (KTK>)


Klavs Klavsen wrote:
> why do I get this congestion WARNING.. is it because i just started the
> squid box?
> I have 350 aio processes..

There is little point in going much above the default. In fact it may be
counter-productive. Having 350 threads is certainly a total overkill and
may have a negative impact on performance, especially latency.

KTK> ok.. that's not good then.

> 2001/11/12 19:00:22| squidaio_queue_request: WARNING - Queue congestion

How many disks do you have, and how many requests/second are hitting the
KTK> 2x18gb 10k rpm disk, sitting on a hardware 160mb/s raid 1.
KTk> dunno about the hits... I only have the vmstat output..
KTK> where I got the same Queue congestion warnings.. but there it was
KTK> only running 50 aio procs.. I figured more procs might help.. but
guess not.
KTK> am I incorrect, or am I missing some numbers from the vmstat output..
KTK> the disk didn't seem to be overloaded - only interrupts as you say -
KTK> and yet I get this WARNING.. what can I tune to improve upon this?

If you have a populated cache of hot objects then it may be expected to
see some of these if you cold-start it and suddenly give it a huge flow
of requests, even if the request rate is otherwise within what the
drives can handle.
KTK> ok.fair enough.. I can handle that i happens at startup..

Henrik Nordström
Squid Hacker
Received on Tue Nov 13 2001 - 00:57:39 MST

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 17:04:09 MST