Re: [squid-users] H/W requirement for Squid to run in bigger scene like ISP

On Tue, Jul 15, 2008 at 05:51:50AM -0300, Michel wrote:
> and the whole issue again and again is understated, at least you
> guys admit already dualcores ...
>
> I really do not understand the resistance, there *_IS_NO_* doubth
> that an 8core machine is faster than a twocore - and whatever
> software you put in there it *_IS_* faster, unless it's idle what
> eventually is the problem at all, are your machines idle so you
> don't see it ????

The issue is that squid itself will only take advantage of one core
as squid is single-threaded. If you have a server with 16 cores
running a single instance of squid, it will only ever use one
sixteenth of the total processing capability of the system. It
simply is unable to run on more than one processor

The "dual core is enough" recommendation comes from those running a
single squid instance and maybe some external helpers (diskd,
redirector, authenticator), as well as standard system tasks. In
this setup it's likely that the system won't be taking advantage of
more than 2 cores anyway, and you can often get higher-clocked
processors if you reduce the number of processor cores. Higher clock
speed helps single-threaded processes (such as squid) because they
can run more instructions per second.

In your setup, you are:

> running three squid instances and diskd, firewall and some scripts
> collecting stats and making rrdtool images

Clearly the additional cores are very useful because you're running
multiple instances of squid, and therefore they're able to utilise
the additional cores. This is perhaps a good suggestion for anyone
looking to maximise the throughput of their proxies (especially
given how little extra you pay for multi-core systems). One would
need to do some testing to find out whether the increased ability to
utilise CPU is worth it, or if there'd be too much contention for
disc I/O; but that will be dependent on your configuration and
workload.

It is worth reminding people that "dedicated squid servers" often do
a little bit more than simply run squid, and having additional
processor cores available for maintenance tasks can't hurt. However,
an 8-way system for a dedicated, single-instance squid is just
throwing money away.
Received on Tue Jul 15 2008 - 10:01:55 MDT