On Fri, Jul 15, 2011 at 11:15 AM, Simon Males <[email protected]> wrote: >> The Varnish munin plugins have alerted me a number of times (say less >> then 5) that N dropped work requests (n_wrk_drop) is greater then 1. >> >> According to Kristian Lyngstol's post [1] this is represents when the >> request queue it full. Additionally I believe the overflowed work >> requests (n_wrk_overflow) will always be greater then n_wrk_drop. >> >> I think I should be trying to tackle two issues: Limit requests >> overflowing, followed by increasing the size of the request queue. >> >> Of the below startup parameters I believe thread_pools should match >> the number of cores the server has and increase the maximum number of >> threads to possibly double (from 25 to 50?). >> >> DAEMON_OPTS="-a :80 \ >> -T localhost:6082 \ >> -f /etc/varnish/default.vcl \ >> -S /etc/varnish/secret \ >> -w 10,25,120 \ >> -p listen_depth=8192 \ >> -p log_hashstring=off \ >> -p lru_interval=60 \ >> -p sess_timeout=10 \ >> -p shm_workspace=32768 \ >> -p ping_interval=1 \ >> -p thread_pools=4 \ >> -s malloc,2G" > > As overflow_max is default set to 100%, I believe I essentially need > to increase the number of worker threads to increase the ratio. To > increase the threads, I'll increase the thread_pools.
Since this post, I increased the thread_pools to 8, though today I've had another spurt of dropped work requests. It's definitely related to a sudden rise of traffic, as the dropped requests happen moment after sending an E-Mail to our users. The servers have 16 cores, so I've increased the thread_pools to 16 now. With 10 minimum threads per pool, I now have 160 threads waiting to serve. Hopefully this will minimise the chance of dropping work requests. -- Simon Males _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
