Re: [squid-users] disk partition locations ?

> > -----Original Message-----
> > From: john allspaw [mailto:jallspaw@yahoo.com]

> > yes, we're using squid in a farm with very high performance requirement,
> > as it's doing http acceleration for our origin servers. we're replacing
> > 2disk SATA with 6disk SCSI, and while I gather there are diminishing
> > returns with adding over 3 or 4 spindles, having a decent cache size is
> > probably second in importance. 
> >
> > we'll be going from 2 cache_dirs of 10Gb each to 6 cache_dirs (one on
> > each disk) with 5Gb each. our cache_mem size is 2048mb, which puts us
> > just over the 10mb/1Gb mem-to-disk suggestions, but the boxes have 4Gb
> > of

On 12.09 09:55, Chris Robertson wrote:
> As I understand it, squid only populates cache_mem with newly requested
> objects (not objects from disk), so if you restart Squid, that 2GB of RAM
> is going to lay fallow. Using a smaller cache_mem allows the OS to use
> the rest of the memory to cache disk hits.

If they have 40% mem hit ratio, I wouldn't decrease cache_mem.

I would try to decrease maximum_object_size_in_memory a bit and/or use
memory_replacement_policy heap GSDF to try get bigger % of memory hits for
smaller files and to reduce disk seeks (they are the slowest part) but I
would be very carefull when doing this and check what impact it has on
efficiency and performance.

depending on network utilisation and data on webservers I would try set up
those caches as neighbours and configure multicast ICP between them, maybe
on separate subnet

> > ok, from what you're both saying, I might not have to worry
> > about where to put the 5Gb partitions on these drives, but
> > basically, it can't hurt.  I've been going on the assumption
> > that the most important performance gains will come from 1)
> > the xtra spindles, and 2) the better seek times on the 15K
> > SCSI (versus 7200k SATA) drives.

you should simply put all partitions on start of disks

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