Re: [Dovecot] Scalability plans: Abstract out filesystem and make it someone else's problem
>b) Use threads, either via some library or implement yourself. Each thread of >course uses some extra memory. Also enabling >threads causes glibc to start >using a thread-safe version of malloc() (I think?), which slows things down >(unless that can be avoided, >maybe by using clone() directly instead of >pthreads?). Perhaps libeio (http://software.schmorp.de/pkg/libeio.html) is a good starting point? I don't have any experience with it but it's used by node.js (http://nodejs.org/) for the async I/O stuff. -Sebastian
Re: [Dovecot] Optimizing POP3 performance?
> The main issue here is that qmail-pop3d violates POP3 spec and returns > wrong message sizes. The size that should be reported to POP3 clients is > the one with linefeeds counted as CR+LF pairs instead of plain LFs. This > doesn't seem to break clients, but I don't want to violate specs just to > make things a bit easier. Thanks for the explanation, i suspected something like this. > Of course if you don't care about any of this, you could just as well > modify Dovecot's sources and have it work the same as qmail-pop3d: The patch fixed my problem, the I/O load on the server is now nearly the same as with qmail-pop3d. Thanks Timo, great support!
[Dovecot] Optimizing POP3 performance?
Hello, I recently migrated to Dovecot from Courier-IMAP and i'm very happy with the IMAP Performance and Dovecot in general. The server is running qmail-ldap and i'm still using the qmail pop3 daemon for the POP3 users. Because i want to get rid of qmail completely (switching to exim) i just tried to replace the qmail pop3 daemon with dovecot too. Immediately after the migration the server became basically unusable because of the high I/O Load caused by the dovecot pop3 daemon. I did some debugging and it looks like dovecot opens every old mail in a users maildir and wants to create it's index files etc. I tried running dovecot pop3 with and without "in memory" indexes but this didn't change anything. Is it possible to disable the indexing of the old e-mails completly for pop3? I understand that dovecot is primarily an IMAP Server but i didn't expect the POP3 Performance to be that bad compared to the qmail pop3 daemon (which is very very basic i have to admit). Is there anything i may have overlooked which helps with the POP3 Performance, any patches that disable the unnecessary indexing etc.? If not, what do you guys recommend and use as a pop3 daemon that is fast and stable? I'm using dovecot 1.0.2 (i checked the ChangeLog, doesn't look like upgrading would give better pop3 performance?) and the relevant pop3-config is: mail_location: maildir:~/Maildir:INDEX=MEMORY mail_debug: yes dotlock_use_excl: yes maildir_copy_with_hardlinks: yes mail_executable: /usr/local/dovecot/libexec/dovecot/pop3 mail_plugin_dir: /usr/local/dovecot/lib/dovecot/pop3 pop3_enable_last: yes pop3_uidl_format: %f pop3_client_workarounds: outlook-no-nuls oe-ns-eoh Any hint in the right direction is greatly appreciated Regards, Sebastian Faerber
