[Zope] Re: Squid headaches

[Toby Dickenson]

On Friday 09 May 2003 2:20 am, Wankyu Choi wrote:
> Hi Toby,
>
> I'm terribly sorry to bother you like this. I tried mailling lists but no
> one seems to have the answer :-)

CC zope@zope.org, in case anyone else is interested.

> Squid works great with one glitch: if you pack your ZODB, Squid gives up
> every parent cache peer as **dead**.
>
> Zope seems to get lazy answering the
> calls from Squid when packing is in progress. Raising timeout values as
> high as 20 seconds didn't fix the problem.
>
> Only restarting squid fixes the problem. I even came up with a little
> script to grep cache.log and restart Squid accordingly. But that's too
> kludgy.
>
> Now I have three ZEO clients defined as parent cache peers. They work
> seemlessly barring this problem.
>
> Have you had any trouble like this?

Yes I have seen that, but I am suprised it applies to you.

You are using ICP. right?

A dead peer means that the ICP replies are getting lost. Lost, not just 
delayed. Is squid really saying "dead peer" in cache.log?

Do you have network packet loss?

Or, maybe squid isnt actually declaring the peers as dead... you would get a 
similar effect if you neglected to put the "round-robin" directive on your 
cache_peer lines, which controls how it resonds to delayed ICP responses  (if 
this is the case then you may want to tweak icp_query_timeout for 
performance, but thats a different question)

I am still suprised that this applies to you at all, because you ZEO server is 
on it own machine. right?

Is there anything of interest in cache.log? What about if you turn on full 
debugging in squid.conf?

Can you post a before and after of "Peer Cache Statistics"  page in squid 
cachemanager CGI


-- 
Toby Dickenson
http://www.geminidataloggers.com/people/tdickenson