MUPDATE too busy

[LaurentG]

Hello, Running CyrusIMAP 2.2.8 on Debian Sarge, with a  2 frontends & 3 backends murder, in operational situation. (5000 dayly users, will climb up to 70000 at the end of the year, with an average of 4 mails of 50ko per user/days) The problem :  mupdate chokes in a strange way when frontends receive few hundreds of mails (mailing lists for example), and 300 messages take at least 1 hour 1/2 to get deliverred. My question : what parameters to configure in order to have mupdate answering quickly to frontends under charge? What to listen at, how to get precisely tuned? If more details needed for a precise diagnostic, please tell me. IN DETAILS : When frontends receive hundreds of mails, (eg 300 shared by 2 frontends), approximatively 40 of them go instantly through postfix to the mailbox, and then the  mailq grows up, with  mainly  "cyrus/socket/lmtp timeout", and few "mupdate unreachable" and in mail.info : "connect to cyrus/socket/lmtp read timeout". By this time mupdate says : 21:34:24 accepted connection 21:34:24 login: frontend01 [128.999.99.99] cyrus DIGEST-MD5 User logged in 21:34:24 cmd_find (fd: 26, user/mail.box)   from fd: 26 to fd: 137, and then 21:35:12 accepted connection 21:35:12 "Server too busy, droping connection" >From this point, after   "New worker thread started..."   "Worker thread finished ..." with 250 of these messages within 1second, memory and cpu use climbing by 10% at this time, still 90% of free resources. The next second, log says :   "Server too busy, droping connection" It lasts 30 or 40 second and then mupdate restarts answering "cmd_find" requests from the frondend, exactly 1 each 10 seconds (peacefull fro resources), for 1 minut or so, and then falls again into  "Server too busy, droping connection" ... and so on, alternatively slow activity or unproductive hyperactivity of threads until frontends mailq's are empty. My confs: FRONTEND SERVER postfix main.cf: initial_destination_concurrency = 200 mailbox_transport = lmtp:unix:/var/run/cyrus/socket/lmtp lmtp_destination_concurrency_limit = 200 cyrus.conf mupdate cmd="mupdate" listen=3905 prefork=1 lmtp cmd="lmtpproxyd" listen="/var/run/cyrus/socket/lmtp" prefork=5 maxchild=50 imapd.conf allowusermoves: yes allowallsubscribe: 1 lmtp_downcase_rcpt: true proxyservers: cyrus mupdate_server: mymupdate mupdate_port: 3905 mupdate_username:  cyrus mupdate_authname: cyrus mupdate_password:  password! #mupdate_retry_delay #mupdate_workers_start #mupdate_workers_minspare MUPDATE SERVER cyrus.conf mupdate cmd="mupdate -m" listen=3905 prefork=1 maxchild=100 imapd.conf lmtp_downcase_rcpt: true proxyservers: cyrus proxy_authname: cyrus proxy_password: password! #mupdate_retry_delay #mupdate_workers_start #mupdate_workers_minspare Thank you for help. --- Cyrus Home Page: http://asg.web.cmu.edu/cyrus Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html