Re: [squid-users] Optimal maximum cache size

From: Amos Jeffries <squid3@dont-contact.us>
Date: Tue, 06 Nov 2007 21:48:54 +1300

Paul Cocker wrote:
> I assume the in-memory index is in addition to the memory_cache? So if
> you have a 100GB disk cache you would need 1GB RAM... but that would
> only cover the index and so you would need more memory for squid itself
> and the memory_cache?
>

I believe so. Plus memory for all the ACLs and active connections etc.
Squid is unfortunately very RAM hungry and nobody has sponsored much in
the way of memory optimisation in a long while.

Amos

>
> Paul Cocker
>
> -----Original Message-----
> From: Amos Jeffries [mailto:squid3@treenet.co.nz]
> Sent: 05 November 2007 23:44
> To: Paul Cocker
> Cc: squid-users@squid-cache.org
> Subject: Re: [squid-users] Optimal maximum cache size
>
>> Is there such a thing as too much disk cache? Presumably squid has to
>> have some way of checking this cache, and at some point it takes
>> longer to look for a cached page than to serve it direct. At what
>> point do you hit that sort of problem, or is it so large no human mind
> should worry?
>> :)
>>
>> Paul
>> IT Systems Admin
>
> Disk cache is limited by access time and ironically RAM.
>
> Squid holds an in-memory index of 10MB-ram per GB-disk. With large disk
> caches this can fill RAM pretty fast, particularly if the cache is full
> of small objects. Large objects use less index space more disk.
>
> Some with smaller systems hit the limit at 20-100GB, others in cache
> farms reach TB.
>
> As for the speed of lookup vs DIRECT. If anyone has stats, please let us
> know.
>
> Amos
>
>
>
>
>
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Received on Tue Nov 06 2007 - 01:49:07 MST

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