Hi Dmitry, It says what it says: you configured HAProxy to manage queue to protect your servers. during your workload, a request remain in queue for too long (1s) so HAProxy simply return an error.
Now the question is why such situation. Simply because your queue management is improperly setup (either increase minconn and or decrease fullconn) and combined to a server which might be quite slow to answer leading HAProxy to use queues. Or you met a bug :) We need the full configuration and log lines around the sQ event (right before and right after), so we may help. Baptiste On Wed, Oct 7, 2015 at 3:18 PM, Dmitry Sivachenko <[email protected]> wrote: > Hello, > > I am using haproxy-1.5.14 and sometimes I see the following errors in the log: > > Oct 7 08:33:03 srv1 haproxy[77565]: unix:1 [07/Oct/2015:08:33:02.428] > MT-front MT_RU_EN-back/<NOSRV> 0/1000/-1/-1/1000 503 212 - - sQ-- > 125/124/108/0/0 0/28 "POST /some/url HTTP/1.1" > (many similar at one moment) > > Common part in these errors is "1000" in Tw and Tt, and "sQ--" termination > state. > > Here is the relevant part on my config (I can post more if needed): > > defaults > balance roundrobin > maxconn 10000 > timeout queue 1s > fullconn 3000 > default-server inter 5s downinter 1s fastinter 500ms fall 3 rise 1 > slowstart 60s maxqueue 1 minconn 5 maxconn 150 > > backend MT_RU_EN-back > mode http > timeout server 30s > server mt1-34 mt1-34:19016 track MT-back/mt1-34 weight 38 > server mt1-35 mt1-35:19016 track MT-back/mt1-35 weight 38 > <total 18 of similar servers> > > So this error log indicates that request was sitting in the queue for timeout > queue==1s and his turn did not come. > > In the stats web interface for MT_RU_EN-back backend I see the following > numbers: > > Sessions: limit=3000, max=126 (for the whole backend) > Limit=150, max=5 or 6 (for each server) > > If I understand minconn/maxconn meaning right, each server should accept up > to min(150, 3000/18) connections > > So according to stats the load were far from limits. > > What can be the cause of such errors? > > Thanks!
