On Mon, Feb 13, 2012 at 5:54 AM, Jan-Frode Myklebust <janfrode@tanso.net> wrote:
We've been collecting some stats to see what kind of benefits UP/SquirrelMail's IMAP Proxy in for our SOGo webmail users. Dovecot is running in High-performance mode http://wiki2.dovecot.org/LoginProcess with authentication caching http://wiki2.dovecot.org/Authentication/Caching
During the weekend two servers (webmail3 and webmail4) has been running with local imapproxy and two servers without (webmail1 and webmail2). Each server has served about 1 million http requests, over 3 days.
server avg. response time # requests
webmail1.example.net 0.370411 1092386 webmail2.example.net 0.374227 1045141 webmail3.example.net 0.378097 1043919 imapproxy webmail4.example.net 0.378593 1028653 imapproxy
ONLY requests that took more than 5 seconds to process:
server avg. response time # requests
webmail1.example.net 26.048 1125 webmail2.example.net 26.2997 1080 webmail3.example.net 28.5596 808 imapproxy webmail4.example.net 27.1004 964 imapproxy
ONLY requests that took more than 10 seconds to process:
server avg. response time # requests
webmail1.example.net 49.1407 516 webmail2.example.net 53.0139 459 webmail3.example.net 59.7906 333 imapproxy webmail4.example.net 58.167 384 imapproxy
The responstimes are not very fast, but they do seem to support the claim that an imapproxy isn't needed for dovecot.
Out of curiosity, are you running dovecot locally on those webmail servers as well, or is it talking to remote dovecot servers? I ask because I'm looking at moving our webmail from an on-box setup to a remote pool to support director and was going to look into whether running imapproxyd would help there. We don't bother with it in the local setup, since dovecot is so fast, but remote (but still on a LAN) might be different. Though imapproxyd seems to make (wait for it...) squirrelmail unhappy (complains about IMAP errors, when sniffing shows none), though I've not bothered to debug it yet.