Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 13 Apr 2000 14:55:44 -0400 (EDT)
From:      mi@privatelabs.com
To:        Chris Dillon <cdillon@wolves.k12.mo.us>
Cc:        questions@FreeBSD.ORG
Subject:   Re: configuring squid
Message-ID:  <200004131855.OAA27159@misha.privatelabs.com>
In-Reply-To: <Pine.BSF.4.20.0004131311540.74405-100000@mail.wolves.k12.mo.us>

next in thread | previous in thread | raw e-mail | index | archive | help
13 Apr, Chris Dillon wrote:
=Snipped from freebsd-scsi, this is only appropriate for -questions.

Sorry,  I thought,  SCSI people  may have  something to  say about  this
drives and how to best use them :)

= On Thu, 13 Apr 2000 mi@privatelabs.com wrote:
=
= > Hello! I'm setting  up a fairly big squid server  with two 45Gb (but
= > slow) SCSI SEAGATE ST446452W (external).
= >
= > I wonder if I  should use ccd to make one  90Gb interleaved array of
= > them or use them separately and tell Squid about the two independent
= > partitions...  Speed  is  the  only factor  --  I  understand,  that
= > separately they'd be easier to manage...
=
= Keep them separate. Squid  load-balances among multiple cache_dirs. If
= speed is the  biggest factor, you really should be  using many smaller
= drives  with a  single cache_dir  on each  one, instead  of two  large
= drives.

We are likely to  be serving big files rather then  many files -- that's
what I mean by big -- images  instead of pages :) The load balancing can
be done  by squid (in user  space) or by ccd-driver  (in kernel). What's
more efficient?  Squid, because it  know what  its dealing with  and can
adapt or ccd because it is simpler and uses predetermined interleaf?
 
= Keep in mind you're also going to need a lot of memory for a full 90GB
= cache. You need  at least 10MB RAM  per 1GB of cache (this  is from my
= personal  experience with  Squid, and  does not  include OS  overhead,
= filesystem cache,  or anything else), so  you'll need at least  1GB in
= there.

Thanks, that's  very valuable  info... Anything special  I need  to tell
newfs when building the filesystems?

= Since you're  also going to be  using two large disks  instead of many
= smaller ones, you'll  want plenty of RAM available  for the filesystem
= cache  and  to  increase  Squid's cache_mem  significantly  above  the
= default of  8MB to  hold the  most popular  objects without  having to
= fetch them from disk often.

Fetching them from the proxy's local disk  does not bother me as much as
having to  re-fetch them from  the source,  which can be  seriously time
consuming...  We also  expect the  fairly uniform  popularity among  the
objects, so caching in memory does not buy much vs. caching on disk.

= How  many requests  per second  are you  expecting during  peak times,
= anyway?

I  don't even  know :)  But it  will  be in  thousands --  we will  have
multiple such squids humming next to each other -- with multiple disks.

Thanks. Yours,

	-mi





To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200004131855.OAA27159>