On 21/11/2011 1:33 a.m., benjamin fernandis wrote:
> Hi All,
>
> I configured squid box to get good cache performance and for that i
> set cache_mem and object size in cache.
>
> cat /etc/squid/squid.conf | grep cache_mem
> cache_mem 6144 MB
>
> cat /etc/squid/squid.conf | grep -i maximum_object_size_in_memory
> maximum_object_size_in_memory 1 MB
>
> And whenever i check memory usage at OS level while squid is serving
> to traffic. it shows me
>
> free -mto
> total used free shared buffers cached
> Mem: 7995 345 7650 0 30 78
> Swap: 8999 0 8999
> Total: 16995 345 16650
>
>
> So as per my squid setup i set 6GB , So why free -mto showing me that
> only 345 mb is used and 7650 mb is free.
>
>
> As per my understanding , if i assign 6GB RAM to squid then 6GB will
> be deducted from my actual memory and then OS has that remaining
> amount of memory.
>
> My perception is right ?
Yes your understanding is generally correct.
There is one circumstance I can think of when the OS might show lower
than cache_mem usage. That is when memory pooling control has been
disabled when building Squid. In that case Squid will not pre-allocate
any memory for use.
>
>
> What is the purpose of --enable-async-io option in squid?
To enable Asynchrnous I/O (AIO) for threaded read/write to disks. This
is required for AUFS.
> i read on internet that it enable more performance while using more
> thread with that option
Yes. Up to the amount of AIO threads your disk controller can work with
efficiently. There is a point at which the threads become too many for
the controller and things get slow again. I'm not personally aware what
that upper limit is.
>
> is it correct information which i have ?
>
> My squid version is Squid Cache: Version 3.1.15
>
> i used squid rpm which i have from my fedora 15 64 bit os in that i
> can't have that option is enabled
>
> so this option is really useful for better performance in high network traffic ?
See above. Only if you are disk caching using AUFS.
Amos
Received on Mon Nov 21 2011 - 04:54:10 MST
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