On 07/04/2012 04:49 AM, Mr J Potter wrote:
Hi all,
thanks for your responses...
versions - I use the standard ones with Debian squeeze (2.7.stable9 and 3.1.6)
Yes there are lots of helpers - 25 NTLM helpers and 10 squiduguard
helpers, so this could account for slow reconfig.
I have seen a performance as low as 1 second per helper for a
Squid process of approximately 4 GB.
How large is your Squid process and how long does it take to
start the helpers?
Upgrading to 3.2 seems like a good bet - are there ready-rooled squid
3.2 debs available for Squeeze or do I have to make my own?
We currently run squid in 3 different flavours of authentication -
NTLM for PCs, ident for macs and digest for guest network, so have 3
distinct squid setups running on our proxy server. Would it be worth
setting these all up as non-caching, then set up a parent caching
server, or will setting them up as cache peers make them share their
caches at all?
This would work well, IF
the "non-caching" Squid has a small memory footprint and needs all the
helpers and the parent Squid has a large memory footprint and
does not need helpers.
Maybe the child can have a small memory cache instead of no cache.
Squidguard also needs more resources than ufdbGuard since it
uses 10 database caches and a database on disk (which is cached in
the file system buffers) where ufdbGuard uses one copy of
the URL database in its own memory. The database format of
squidguard uses 2-4 times more bytes than the format of
ufdbGuard reducing further the need for memory resources.
Marcus
cheers
Jim
UK
On 2 July 2012 14:44, Marcus Kool<marcus.k...@urlfilterdb.com> wrote:
Squid reconfigure can indeed take a long time. Especially when Squid
uses lots of memory and starts helpers. Starting helpers takes a
large amount of kernel resources when Squid is large, e.g. 2+ GB
since it forks itself and replaces its copy by a new process. The
fork can take a long time. If you use a URL rewritor you can
easily have 24 or more of them and this makes 24 copies of a large
process.
How large is squid ?
Can you post the output of
ps -o pid,stime,sz,vsz,rss,args -C squid
I wrote a test program to test the performance of forking X times
a large process. I can post it if you are interested.
Marcus
On 07/02/2012 05:08 AM, Mr J Potter wrote:
Hi all,
Does anyone have any tips on how to fix this issue:
We've just moved to squid3 from squid2, and now when we do squid3 -k
reconfigure we get about 30 seconds of squid refusing/failing to
forward requests while it rejigs itself. I don't know if this is
squid3 rescanning the cache or doing something with squidguard (we
have a fairly complex+large squidguard setup)? I don't think this
happened with squid2.
What can we do to make this less noticeable?
- make it reconfigure faster?
- multiple squid servers - can we do failover somehow (either proxy
DNS record points to them both, or they automatically redirect (is
this what cache peers are for?))?
- go back to squid 2 - I didn't see any end user benefits of squid3
over squid2...
any help would be greatly appreciated.
thanks
Jim Potter
UK