Hi, Web search turned no results to this problem: We have a small site running private e-mail for maybe 12 people, dovecot is used by Postfix-SASL and IMAP clients. PROBLEM: When starting dovecot, after a few hours, IMAP clients are no longer able to connect. Thunderbird indicates that connection is refused. On the server, we see 100 dovecot/imap-login processes. This is the process limit. If we increase the process limit to 200, same thing, we survive a few hours longer but eventually we're seeing 200 imap-login processes and rejected connections. When listing TCP connections via lsof, there are only around 30 connections open to IMAP and we have exactly the same amount of dovecot/imap processes. These connections are held by 30 dovecot/imap-login processes. The other 70 dovecot/imap-login processes seem to do nothing. They're all sitting in "epoll_wait(14," according to strace but don't have TCP connections open. The only way out of this that we have found is re-starting dovecot every few hours. BTW, service_count = 1 for improved security. Dovecot Version: 2.3.4.1 (f79e8e7e4) Interestingly we were using nearly the same config on our old server with 2.2.13 and did not see this issue. Any ideas how to solve that properly? Thank you, Wolfgang
> On 02/02/2021 14:59 Wolfgang <adminkram at tripelspark.de> wrote: > > > Hi, > > Web search turned no results to this problem: > > We have a small site running private e-mail for maybe 12 people, dovecot > is used by Postfix-SASL and IMAP clients. > > PROBLEM: When starting dovecot, after a few hours, IMAP clients are no > longer able to connect. Thunderbird indicates that connection is refused. > > On the server, we see 100 dovecot/imap-login processes. This is the > process limit. If we increase the process limit to 200, same thing, we > survive a few hours longer but eventually we're seeing 200 imap-login > processes and rejected connections. > > When listing TCP connections via lsof, there are only around 30 > connections open to IMAP and we have exactly the same amount of > dovecot/imap processes. These connections are held by 30 > dovecot/imap-login processes. > > The other 70 dovecot/imap-login processes seem to do nothing. They're > all sitting in "epoll_wait(14," according to strace but don't have TCP > connections open. > > The only way out of this that we have found is re-starting dovecot every > few hours. > > BTW, service_count = 1 for improved security. > Dovecot Version: 2.3.4.1 (f79e8e7e4) > > Interestingly we were using nearly the same config on our old server > with 2.2.13 and did not see this issue. > > Any ideas how to solve that properly? > > Thank you, > WolfgangHi! Can you provide output of `doveconf -n`? Also, would it be possible to try out with latest version at https://repo.dovecot.org? Aki
On 02 Feb 2021, at 05:59, Wolfgang <adminkram at tripelspark.de> wrote:> hen listing TCP connections via lsof, there are only around 30 > connections open to IMAP and we have exactly the same amount of > dovecot/imap processes. These connections are held by 30 > dovecot/imap-login processes. > > The other 70 dovecot/imap-login processes seem to do nothing. They're > all sitting in "epoll_wait(14," according to strace but don't have TCP > connections open.Have you tried reducing the number from 100 to, say, 30? But as Aki said, doveconf -n is crucial, especially since you upgraded from an older version. -- I draw the line at 7 unreturned phone calls.