Re: [squid-users] squid smp fails -k reconfigure

On 06/09/2014 08:38 AM, Fernando Lozano wrote:

>>> I find very strange that workers 6 and 5 try to get aufs cache stores.
>>> They are supposed to be the rock store disker and the coordinator! My
>>> squid.conf has:
>>>
>>> workers 4
>>> cache_dir aufs /cache/worker${process_number} 25000 16 256
>>> min-size=31001 max-size=346030080

>> AUFS store is not SMP-aware. You should not be using it in SMP
>> configurations IMO.

> Squid configuration examples and the wiki page about SMP tells to use
> ${process_number} to setup exclusive aufs caches for each worker.

> If we should not use anything except rock store for SMP this should be
> explicit in the docs/wiki/faq.

The opinions of what should and should not be used for SMP vary. Squid
documentation reflects the lack of consensus. I am sharing my own
opinion. YMMV.

>>> Is squid -k reconfigure working well for everyone else with SMP?
>> Reconfigure does not work well without SMP. It works even worse with
>> SMP. Log file rotation is an example of a problematic area specific to
>> SMP.
>
> That's also news to me. I could not find anything on squid-cache.org
> stating reconfigure is problematic and should be avoided.

Whether restart is better than reconfigure depends on your specific
environment, needs, and fears. There is no general rule. For example,
reconfigure may leak 100 MB of RAM in some environments. That could be
OK if you have plenty of spare RAM and reconfigure infrequently. The
same could lead to disasters if you are tight on RAM or reconfigure a
few times per hour.

Moreover, Squid developers have different opinions regarding fixing some
of those leaks. For example, a recent patch fixing some of the leaks was
not committed in leu of waiting for more complex patches with the same
user-visible effect.

Memory leaks is just one example. There are other problems with
reconfigure such as rejecting some incoming connections. I do not have a
complete list and YMMV.

> Just to make sure I understand correctly: I shoud restart squid, instead
> of reconfiguring, when changing acls, and cope with the downtime?

Sorry, I do not know the answer to that question because it depends on
many local factors. I recommend:

  * short-term: testing and selecting the least of the two evils;
  * long-term: helping improve reconfigure support.

HTH,

Alex.
Received on Mon Jun 09 2014 - 15:11:19 MDT