[Dovecot] Dovecot "open files" (again?)
I'm a new dovecot user, just began using it last week. I switched from courier because my research showed that Dovecot did indexes, and allows me to store them anywhere I chose. I did this, and it fixed some severe disk IO issues that my server had. (25k horde only webmail install using imap proxy).
I'm using quotas, and by default had it set to 'dirsize'. my postfix is already creating 'maildirsize' files, so I opted to change dovecot to use this instead.
However, when I do, I run into the "too many open files" issue that's been reported many times on the list. I've seen a lot of mention of too many open files, but I haven't seen it related to the quota type used. It's possible that simply my using 'dirsize' as the quota type slows things down enough to not have the issue? I don't really know.
Anyhow. I doubled my max open files in FreeBSD's /boot/loader.conf to: kern.maxfiles="24656", but to no avail. When I have it set to maildirsize, the open files on the system grows uncontrollably. Under normal use, it's somewhere below 5k:
sysctl -a | grep openfiles kern.openfiles: 4415
I looked into the patch mentioned here:
- http://www.dovecot.org/list/dovecot/2006-November/017536.html
- http://dovecot.org/list/dovecot-cvs/2006-November/006776.html
Those patches already appear to be in rc15, which I'm already running (Via FreeBSD's ports). I also applied the patch mentioned here awhile back:
and rebuilt, but it didn't help out either. There are also freebsd specific notes on forcing a limit on dovecot itsself using login.conf, but that wouldnt really fix anything, it would just cause dovecot to not interfere with other running daemons.
Any thoughts? TSS, you mention a few times in these notes that you're unable to reproduce this. Perhaps try with the maildir as quota?
More details about my setup:
- FreeBSD 4.8 (yea, I know)
- Imapproxy (http://www.imapproxy.org/)
- Postfix to create maildir++ maildirsize folders
- MySQL backend
The work of this is spread out between several servers, dovecot is running on the server that's the final SMTP delivery location, and has local disks with the maildirs.
--falz
On Fri, 2006-12-15 at 10:05 -0600, falz wrote:
So you tried something like "quota=maildir:storage=123456"?
How quickly? By doing what exactly? Just logging in, opening a mailbox, saving a new mail, ..?
Any thoughts? TSS, you mention a few times in these notes that you're unable to reproduce this. Perhaps try with the maildir as quota?
The previous problems seemed to have been only with NetBSD 2.0 and kqueue enabled, and I think it's a NetBSD bug.
I looked through the maildir quota code, and I do actually see one fd leak in there, but it happens only when deinitializing the quota, so practically it doesn't matter.
You sent a lsof of the dovecot process, but assuming you hadn't dropped out thousands of lines from it, it probably wasn't the problematic process. Quota code is handled by imap process, so check that instead, and check also that lsof is returning thousands of lines. If it isn't, then it's something else that's eating the fds..
On 12/15/06, Timo Sirainen <tss@iki.fi> wrote:
That's exactly. the exact lines I toggle between are:
quota = dirsize:storage=102400 quota = maildir:storage=102400
When it's set to maildir, the openfiles go up at an incredible rate.
It's on a live system, probably with at least 20 imap connections (imap proxy is running on another server, it's handling more users than that). So, simply toggling this setting, reloading dovecot. probably takes 4 or so minutes for it to go from a few thousand to 20k.
I saw some older threads, in 2004 and 2005. Unsure if was completely related or not.
I can't seem to successfully get a full lsof piped to a file when i'm running quota's with the maildir type- I'm assuming because the # of open files are growing until it hits the system limit.
If I can, I'll see if I can lock the system down and deny logins to all except myself, do a test login with only one user, and still see if it happens.
I should also note that here's what I've got for some of the speed tweaking things in dovecot. Some of this was just guesswork, going on what the wiki and some mailing lists say.
login_process_size = 32 login_process_per_connection = no login_processes_count = 15 login_max_processes_count = 512 login_max_connections = 1024
For the hell of it, I changed per_connection back to 'yes' (I had only changed it because docs say it's faster that way, which is what I'm shooting for). The same thing still seems to happen- it was in the 2k range for open files prior to this (right now = not many users), and after only about 2 minutes it's already at 5k, and never going down.
Any other debugging info you're looking for, other than lsof output? Is there any way that you can think of that I can find how many active login, auth, or whatever else processes are actively happening at one time?
thanks --falz
I guess this was fixed by rc20's maildir quota fd leak fix?
I had not looked at the status for awhile, but was reading the changelog earlier this week and it looks like there were a few leak fixes between rc15, which I was on, and rc22. I did upgrade, earlier this week, and it did fix it!
Thanks much.
--falz
participants (2)
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falz
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Timo Sirainen