Re: [squid-users] cache_mem

From: Amos Jeffries <squid3_at_treenet.co.nz>
Date: Fri, 23 Jan 2009 14:33:39 +1300

Paul Cocker wrote:
>> -----Original Message-----
>> From: Amos Jeffries [mailto:squid3_at_treenet.co.nz]
>> Sent: 21 January 2009 23:42
>> To: Chris Robertson
>> Cc: squid-users_at_squid-cache.org
>> Subject: Re: [squid-users] cache_mem
>>
>>> Paul Cocker wrote:
>>>> Simple one I hope
>>>>
>>>> Once you have squid up and running and know its memory use and
>>>> overall system memory use, should cache_mem be set as a
>> percentage of
>>>> the free memory available, or should you be leaving a
>> large amount of
>>>> memory for the use of the OS file cache and keeping squid'
>> cache_mem
>>>> at a smaller value like 64MB?
>>>>
>>> 1) Squid's handling of large objects (1MB+) in memory can be CPU
>>> intensive.
>>>
>>> 2) Squid does not pull objects from the disk cache into the
>> memory cache.
>>> Given those two facts, I use a smaller cache_mem value (64
>> or 128 MB)
>>> and leave the rest for the OS.
>> (1) is only relevant to squid-2. Squid-3 handles large file
>> in-memory a lot better. But (2) still occurs in both, so it's
>> only partial improvement on initial handling.
>>
>> Amos
>>
>>
>
> How intensive is intensive? At the moment squid is averaging a mere 2.4%
> processor time.

IIRC older Squid-2 had to step a linked-list the length of the object in
4KB chunks to perform one of the basic operations (network write I think).

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE5 or 3.0.STABLE12
   Current Beta Squid 3.1.0.3
Received on Fri Jan 23 2009 - 01:33:37 MST

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