Hi Amos, Amos Jeffries a écrit : > On Mon, 16 Nov 2009 16:40:16 +0100, "David B." <haazeloud@xxxxxxxxx> > wrote: > > [Snip] > > I have not seen FIN_WAIT1 before, but often see FIN_WAIT like this when > Squid is receiving a lot of connections. > > I think its due to squid using sockets for short times (non-persistent > connections) and moving on. The system TCP timeouts are much longer. > Maybe, it's quite strange. > [Snip] > Maybe yes, maybe no. > I assume the LVS works on TCP-link connections so one persistent > connection is not broken up. Thats the only breakage that could make this > issue worse. > > Normal LVS would be helping a bit by spreading the load off the problem > Squid boxes. > Sorry i haven't give you all details. In fact, i've got an LVS in front, acting as a TCP/IP load balancer, no persistent session there, it's a round robin. Then, TCP request is transmitted to a squid box. This box will answer to the client directly (DSR or direct routing mode). I'm just wondering if activate "session" on the LVS to force someone to join the same squid boxe will help. > >> Perhaps my load is too high and i need to tune kernel via sysctl, but i >> can't figure what to do. For now, i've tried several things and i can't >> solved this issue. >> > > You may want to check: > * persistent connections is turned on (squid.conf) > On by défault i think, but i will force this to on to test. > * system socket timeouts > System socket or squid related like persistent_request_timeout ? > * half-closed clients is off. (squid.conf) > We've tried on and off on several boxes, no change for now. > Hopefully someone with real finger-time at high performance systems will > be able to point at specific tuning knobs which are helpful. > I hope too. I can give the squid conf if needed. :) > >> Here's some squid stats : >> HTTP/1.0 200 OK >> Server: squid/3.0.STABLE8 >> Mime-Version: 1.0 >> Date: Mon, 16 Nov 2009 15:35:35 GMT >> Content-Type: text/plain >> Expires: Mon, 16 Nov 2009 15:35:35 GMT >> Last-Modified: Mon, 16 Nov 2009 15:35:35 GMT >> X-Cache: MISS from ww.xx.com >> X-Cache-Lookup: MISS from ww.xx.com:80 >> Connection: close >> >> Squid Object Cache: Version 3.0.STABLE8 >> Start Time: Mon, 09 Nov 2009 09:03:56 GMT >> Current Time: Mon, 16 Nov 2009 15:35:35 GMT >> Connection information for squid: >> Number of clients accessing cache: 254750 >> Number of HTTP requests received: 337655902 >> Number of ICP messages received: 0 >> Number of ICP messages sent: 0 >> Number of queued ICP replies: 0 >> Number of HTCP messages received: 0 >> Number of HTCP messages sent: 0 >> Request failure ratio: 0.00 >> Average HTTP requests per minute since start: 32244.7 >> > > avg 537 req/sec. Nice :) > > Are you able to provide CPU details sop we can add this to > http://wiki.squid-cache.org/KnowledgeBase/Benchmarks ? > Squid box is a VM under Xen. CPU : 2 vcpus (xen), like 2 cores of an intel Xéon E5430 2.66 Ghz Memory : 10 Go Disks : VM storage on a hardware RAID 5 controller. FS for cache : XFS with noatime,nodev,nosuid,noexec Under peak, CPU is low : (max is 200%, 100% per core) idle : 160% iowait : 30% system & user : 10% I hope this will help. David.
