Re: cache dir

Yomler wrote:
>
> If we have one cache-dir per physical disk, how squid will deal with a disk
> failure ?

It depends a bit on how your OS handles the failure, and when it is
detected. Squid will probably be a bit upset until you remove that
cache_dir entry from suqid.conf and restart it.

> If we use RAID 5, how many logical disk is it better to mount ?

If using RAID 5, then the I/O performance is effectively degraded to
only little more than one drive. This is due to the "random" I/O pattern
with small read/writes, which is very bad for RADI5 performance (RAID5
likes big or fully sequential read/writes).

> Is it better to split the RAID 5 array in several logical disks ?

Marginally.

> Is it worth to get disks in RAID 5 array ?

Probably not, but it is probably worth the effort to investigate a bit
of research in how you want disk failures to be handled. For example it
shouldn't be that hard to have a survelance script which automatically
takes out the relevant cache_dir line from Squid if a disk should fail.

--
Henrik Nordstrom
Squid hacker