Re: [squid-users] File system recommendations for squid cache.

On 24.04 00:58, Charlie Johnson wrote:
> >> The company I'm working for uses squid for caching and access control.
> >> We use 3 Dell 2650s for squid, with a 3 disk (U320 10K RPM) RAID-0
> >> (stripe set) for the cache partition on each server.

> >What OS?

> >It's recommended to split that stripe into separate drives. Squid does
> >not benefit from striping. Squid automatically splits the load on the
> >available drives (cache_dir), so striping only makes long term
> >maintenance of your system harder as any change to the cache would mean
> >loosing the whole cache.

> The OS is Linux 2.4.29 (Debian 3.0_R4)
> What is the recommended size of each cache_dir (disk)?

> Still, with several smaller independent disks for the cache_dirs, what
> filesystem is recommended for this use?

http://www.squid-cache.org/Doc/FAQ/FAQ-4.html#ss4.14

it is the same for every drive, and it doesn't matter if you use separate
drives or strip from this point of view.

> >> What file system is recommended for use on the cache partitions?
> >> We have tried with ext2, xfs and reiserfs 3.6.
> >>
> >> First we thought using ext2 (no additional configuration) would be a
> >> good idea, since there is no journaling etc. The performance sucked.

> >What cache_dir type did you use? aufs is recommended for linux.
> >The default "ufs" cache_dir type by design won't perform in higher
> >loads as each I/O operations blocks the whole Squid process..

That's it. first set up aufs, then try playing with different filesystems.

Some tests showed that ext2/3 behaves better than e.g. reisersfs for squid
cache. I didn't try but I think ext3 should be good (journalling slows it
down a bit, but in case of crash you won't have to wait long time until fsck
fixes all).

> cache_dir diskd /var/spool/squid 65536 64 1024

the count of first-level and second-level directories should be close to
eash other and I don't recommend you increasing the second one (the default
is '16 256').

The number of directories really used depends on number of object stored in
the cache and therefore on maximum_object_size.

I've used '256 256' on 30GB drive, but only 64 of first-level directories
got used, so I decreased it to '64 256'. The average object size is ~13 KB
so I had ~2 milions of objects on that dir.

If you have 70 GB of space, I'd use '128 256'. But you are going to split
that up to 3 disks, each of lower size, right? In such case, '32 256' should
be enough.
Our caches,

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