Re: [squid-users] question in cache mem in squid 3

On 1/08/2013 2:07 a.m., Carlos Defoe wrote:
> i have one question.
>
> Can i adjust my system memory usage (by changing cache_mem, the only
> ammount changeable) to an ammount where no space is left for that
> "cache"? If a linux machine with squid uses the more RAM you provide,
> for that "cache" thing, it must be useful. It is better to leave some
> space for that, or not?

You can change system memory usage by Squid by changing any of the
parameters which directly or indirectly consume that memory.

The most noticable is cache_mem, which consumes about 1.015 GB for every
1GB it is set to.
The less noticable are cache_dir which consume about 15MB of memory per
GB of cache size.
The helper result caches.
The two DNS result caches (one for each type of forward/reverse lookup).
The database of active clients.
Active transaction buffers (read_ahead_gap amount of memory is concumed
once per FD).
Idle connection pool and all the buffers associated with those connections.
Which components are used by a transaction also affect memory usage (one
ICAP request consumes twice as many FD and memory buffers as a non-ICAP
equivalent).
Even tuning timeouts affects total memory needs, as some transactions
end and release their memory more quickly.

Lots of ways to tune Squid memory usage. Some more effective than others
and most trading traffic speed for memory.

Amos
Received on Wed Jul 31 2013 - 14:29:31 MDT