Travis Derouin wrote:
Great, thanks for the suggestions! I have some
questions.
I don't believe we've had this problem,
squid should keep serving cached
pages reasonably efficiently until the filedescriptor limit is reached or
you run out of CPU. You might want to check that there is in fact no
communication back to the webserver when squid serves "cached" pages. It
might be doing an If-Modified-Since (IMS) refresh, or a full request. If it
is, then you need to make sure you're sending the right Expires and
Cache-Control headers.
The correct headers are just
Cache-Control: s-maxage=2678400, must-revalidate, max-age=0
which are generated in Outputpage.php, right?
I'd rather have it confirmed by canonical evidence rather than by relying on
us, after all, we might be doing it wrong too. Try tcpdump, or if you can't
do that, the webserver logs, or if you can't do that either, the squid logs
will tell you things like "TCP_IMS_HIT" or "TCP_MISS".
Make sure
you're using epoll not poll. There's the possibility that your
select loop is becoming too slow as the connection count increases. You'll
see high system CPU and a high select loop period in cachemgr.cgi.
I'm not sure what epoll and poll are and can't seem to find any
documentation on them, can you point me in the right direction?
http://www.google.com/search?epoll+squid
I believe it's in Squid 2.6:
http://www.squid-cache.org/mail-archive/squid-users/200606/0416.html
I'm not sure how you're meant to tell whether it's running or not, besides
the dramatically lower system CPU.
-- Tim Starling