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
