Thanks Stephan!
I will fold your information into the FAQ as this is a topic which comes up semi regularly on the list. Nicola On Fri, Dec 16, 2016, at 07:54 PM, Stephan Lauffer via Info-cyrus wrote: > Hello! > > While testing 2.5 we struggled over (known) problems like this...: > > ...ssh can't fork process to run service imaps/ipv4: Resource > temporarily unavailable > > I searchd... and I found your FAQ... > > https://cyrusimap.org/imap/faqs/o-toomanyprocesses.html > > ...and this "tcp_keepalive = 1" hint was doing a good job, but not > fixing our problem completely. Less processes as without this setting > but too many at all. > > Btw we have a murder with 5 backends and each has about 5k mboxes. > With 2.4 we have about 400 imapd processes on the backends (in normal > state) and about 800 on the proxy. Peaks raises this values for sure. > > But we still wasn't able to get over a limit of about 500 imapds on > our new system which is running 2.5. Yesterday night I found our > problem: > > SYSTEMD > > (and not cyrus-imapd-2.5, but 2.5 was running with systemd here...) > > I guess there may be more people out there which may be interested in > a solition (we will add fixes to our systemd scripts of our suse bulds > soon, see > https://build.opensuse.org/package/show/home:nixda:devel/cyrus-imapd). > > The first problem there is: > > Systemd does not care about your /etc/security/limits.conf > > The second problem is: > > Systemd comes with a new limit called "TasksMax". You will find this > limit f.e. in /etc/systemd/system.conf as "DefaultTasksMax=512". But > you will NOT find this limit in "cat /proc/`cat > /var/run/cyrus.pid`/limits". > > The solution is to add a file with a systemd override for this > service. F.e. use the systemctl edit <sevice> command... (like > "systemctl edit cyrus-imapd.service") or place a file in > /etc/systemd/system/cyrus-imapd.service.d/override.conf with f.e.: > > [Service] > TasksMax=2048 > LimitNOFILE=10000 > > The LimitNOFILE is just a guess... maybe you may not need this here. > > After setting this override you will see a status information about > your process count and limit like this: > > # systemctl status cyrus-imapd.service > ● cyrus-imapd.service - The Cyrus IMAP and POP Mail Server > Loaded: loaded (/usr/lib/systemd/system/cyrus-imapd.service; > enabled; vendor preset: disabled) > Drop-In: /etc/systemd/system/cyrus-imapd.service.d > └─override.conf > Active: active (running) since Thu 2016-12-15 20:51:17 CET; > 12h ago > Main PID: 12901 (master) > Tasks: 326 (limit: 2048) > [...] > > > What about adding a short hint to your faq? Yes, it is not a cyrus > problem. And yes, a sysadmin should know... but... I guess systemd in > depth may not be good known as the old ulimit thing and if you are > searching in the web 99% of the hits deal with ulimit. > > > -- > Liebe Gruesse, with best regards > Stephan Lauffer > > Pedagogical University Freiburg - Germany > http://www.ph-freiburg.de/zik/ > Fon/ Fax: +49 761 682 -559/ -486 > ---- > 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 > Email had 1 attachment: > * smime.p7s 8k (application/pkcs7-signature)
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