On 04/21/2017 10:43 AM, dave@evilcigi.eu wrote:
Everything works fine, until I reload dovecot configuration. When that happen, every client is forced to relogin in the same time and that causes a huge system load spike (2-3000 5 min load).
A system load of 3000 means that an average of 3000 processes would like a bit of CPU time, not that the system's unable to *provide* that to them, if only the amount of CPU each needs is small enough. You want to look at the actual percentage of CPU used (and at the total number of processes, to see how close you might be to running out of PIDs).
I was thinking that it would be great, if dovecot wouldn't kick all the users in the same time during reload, but somehow gradually, during specified interval.
That wouldn't help unless the kicked clients, which will likely try to reconnect immediately, *can* reconnect at once; otherwise, at the end of the grace period, you'ld still have 100% of the clients banging on the doors to get back in simultaneously.
So "old" and "new" dovecot would need to run in parallel, with all the incompatibilities and resource restrictions *that* might entail, seeing that there's obviously *something* that changed and prompted you to try and restart dovecot in the first place.
In other words, I don't think that the dovecot code *can* cover all those cases on its own - providing two suitably separate environments (like with Kevin's proxy+docker suggestion) is IMHO the way to go here.
Regards,
Jochen Bern Systemingenieur
Fon: +49 6151 9067-231 Fax: +49 6151 9067-290 E-Mail: jochen.bern@binect.de
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