Re: [squid-users] Veritas filesystems and Squid

Deb Heller-Evans wrote:

> Does any have of any known performance issues using Veritas disk
management
> (and thus, filesystems) with SQUID on Solaris 2.7?

Don't know. I think someone here posted their experiences with it, but
I don't recall if they were good or bad. I know Adrian does some
Solaris experimentation, but I don't recall him using Veritas.

> Also, in reading the documentation on the web, I saw somewhere
recommended
> that RAID5 *not* be used as the target disk(s) for the cache. In
> trying to maintain uptime, should a disk go bad, using RAID5 would
> give us a WIN situation. What are the reasons to NOT use RAID5,
> and do you think they outweigh keeping a system up (ie, RAID5
> allows for the hotswapping of disk drives should it become
> necessary)?

Try RAID5 on all /but/ the cache partitions. Giving you reliability
without the significant performance loss. Now that disk space is so
cheap we do full mirroring on our multi-disk systems for the system/boot
partitions so that if any N-1 of the disks in the system fail it can
continue to operate. So, no tradeoff of uptime for performance is
necessary.

That said, if you must stripe all of the disks for your comfort, you can
probably expect performance to drop by 25-50% on the striped disks.
Though that might be negated to some degree by a good hardware RAID
controller with tons of onboard buffer RAM (or tons of system memory to
smooth out the disk access sluggishness). Whether this "outweighs" the
reliability of RAID5 is up to you. I can't judge that for you since I
don't know if you are going to need every bit of performance you can get
from your hardware or not.

You can find lots more in the mailing lists archives on the subject of
/why/ striped RAID is so bad for Squid performance. Henrik explained it
about 6-9 months ago more clearly and accurately than any other
explanation I've seen, including my own, so searching out his wisdom on
this in the acrhives is probably a good idea if you want to understand
more about it.

Good luck.
                                   --
                      Joe Cooper <joe@swelltech.com>
                  Affordable Web Caching Proxy Appliances
                         http://www.swelltech.com
Received on Fri Aug 17 2001 - 15:46:12 MDT