Re: [squid-users] RE: Squid CPU 100% infinite loop

From: Loïc BLOT <loic.blot_at_unix-experience.fr>
Date: Tue, 11 Jun 2013 19:48:40 +0200

Hello mike,
please look at the number of system file descriptors opened, the squid
limit and the squid user limit. I have this problem on 3.2 and 3.3
because squid was at the FD limit. (look at the system fd limit for
squid, ulimit -n with the squid user)

-- 
Best regards,
Loïc BLOT, 
UNIX systems, security and network expert
http://www.unix-experience.fr
Le mardi 11 juin 2013 à 15:32 +0000, Mike Mitchell a écrit :
> I dropped the cache size to 150 GB instead of 300 GB.  Cached object count dropped
> from ~7 million to ~3.5 million.  After a week I saw one occurrence of the same problem.
> CPU usage climbed steadily over 4 hours from <10% to 100%, then squid became
> unresponsive for 20 minutes.  After that it picked up as if nothing had happened -- no
> error messages in any logs, no restarts, no core dumps.
> 
> I'm now testing again using version 3.3.5-20130607-r12573 instead of 3.2.11-20130524-r11822.
> I've left everything else the same, with the cache size still at 150 GB.
> 
> Mike Mitchell
> 
> On 30/05/2013 08:43:24 -0700, Ron Wheeler wrote:
> 
> > Some ideas here.
> > http://www.freeproxies.org/blog/2007/10/03/squid-cache-disk-io-performance-enhancements/
> > http://www.gcsdstaff.org/roodhouse/?p=2784
> > 
> > 
> > You might try dropping your disk cache to 50Gb and see what happens.
> > 
> > I am not sure that caching 7 Million pages gives you much of an advantage over 1 million. The 1,000,001th most > popular page probably does not come up that often and by the time you get down to a page that is 7,000,000 in the list of most accessed pages, you are not seeing much demand for that page.
> > 
> > Probably most of the cache is just accessed once.
> > 
> > Your cache_mem looks low but is not related to your problem but would improve performance a lot. Getting a few > thousand of the most active pages in memory is worth a lot more than 6 million of the least active pages sitting on a disk.
> > 
> > 
> > I am not a big squid expert but have run squid for a long time.
> > 
> > Ron
> 

Received on Tue Jun 11 2013 - 17:41:44 MDT

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