Hi! A can add another story of that type, but with different setup: We already migrated to 2.5.7 on our ten backends some month ago step by step and upgraded to 2.5.9 lately. We never had any performance issues on them. All of them have done a full "reconstruct -V max" and special-use metadata is set to step in for static xlist missing in 2.5 frontends. Yesterday I did the final step by updating our mupdate server and the murder frontends. No problems on the mupdate server so far. The configs are mostly the same like for 2.4 (except for the changed names). The only key change done was from skiplist to twoskip for all databases: annotation_db: twoskip duplicate_db: twoskip ptscache_db: twoskip mboxlist_db: twoskip seenstate_db: twoskip statuscache_db: twoskip subscription_db: flat tls_sessions_db: twoskip userdeny_db: flat All of them are placed in /var/spool/imap/config except statuscache and tlscache which reside in /dev/shm. After migrating the frontends yesterday evening I already recognized a higher load and decided to keep an eye on it. Our 3 frontends are: CentOS 6 (vmware based) 16GB RAM 4 CPUs They usually have ~4000-4500 concurrent imap(s) connections at peak time and had a load ~1-3 with cyrus 2.4. swap was not used. Today in the morning we had the same connection count with load ~100-250 with cyrus 2.5.9 and twoskip. no swap used. top shows a huge amount of imap processes in running state. Another thing I recognized was that changes in mailboxes.db on backends reached the mupdate server, but didn't come through to the frontends anymore even after 15 minutes. I changed mailboxes.db and tlscache back to skiplist and load went down to 5-15. So, much better but still 5 times as high as with 2.4 and still causing headaches. Currently I have no idea what causes the load besides twoskip (which I can live without since skiplist never caused us any troubles). I compared "USAGE" loglines from two days (2.4) ago to 2.5 with skiplist and twoskip. 2.4 : user: 0.384322, sys: 0.029056 (23538 USAGE lines, 09:00-10:00) 2.4 : user: 0.353515, sys: 0.030814 (25790 USAGE lines, 13:00-14:00) 2.5 ts: user: 0.903491, sys: 0.028196 (23429 ... , 08:00-09:00) 2.5 ts: user: 1.130391, sys: 0.032894 (27709 ... , 09:00-10:00) 2.5 sl: user: 0.864270, sys: 0.026580 (29567 ... , 13:00-14:00) 2.5 sl: user: 1.077462, sys: 0.032952 (25879 ... , 14:00-15:00) Comparing all three I wonder why skiplist makes such a big difference. lmtpd shows now relevant difference for all three. Most likely I will go for horizontal scaling putting a 4th frontend in the line. Greetings, Wolfgang -- Wolfgang Breyha <wbreyha@xxxxxxx> | http://www.blafasel.at/ Vienna University Computer Center | Austria ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ To Unsubscribe: https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus
