Re: [SQU] squid Pbs when high load, async-io, SMP under linux

If using async i/o, are you using Squid 2.2STABLE5+Henrik's patchset?
If not, you will have many problems with performance, and stability at
extremely high loads. 2.3STABLE, and the unpatched 2.2STABLE just are
not reliable for async i/o operation.

I've written an article about tuning Squid on Linux for performance
which may be of interest to you:

http://www.swelltech.com/pengies/joe/squidtuneup/t1.html

The new 2.4 Squid will be even better for async once all the bugs are
worked out.

Increasing the number of threads does improve Squid's request handling
in some cases, assuming you have the processor time, and memory to
accomodate the added threads. Our systems run with 32 threads, usually,
and that seems to be a good average number for the 2.2 Squid on the
types of hardware we build (1-3 disks, and 500-900MHz processors).
However, if you increase the threads beyond what is appropriate for your
hardware, you will find that Squid crashes due to extreme resource
starvation.

Fabien Salvi wrote:

>
> So, more simple (?) :
> If I increase the number of io threads, will I obtain better result and
> will it solve the problem I have with no response to requests ?
>
> Thanks in advance for your help!

                                   --
                      Joe Cooper <joe@swelltech.com>
                  Affordable Web Caching Proxy Appliances
                         http://www.swelltech.com

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