[ext] dovecot 2.3.7.2-1~bionic: Performance issues caused by excessive IO to ~/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.tmp

[Aki Tuomi]

> On 16/10/2019 13:31 Ralf Hildebrandt via dovecot <dovecot at dovecot.org> wrote:
> 
>  
> * Ralf Hildebrandt via dovecot <dovecot at dovecot.org>:
> > * Timo Sirainen <timo at sirainen.com>:
> > 
> > > > BTW: This post is a followup to my "2.3.7 slower than 2.3.6?" post from back in July.
> > > 
> > > Fixed by https://github.com/dovecot/core/commit/5e9e09a041b318025fd52db2df25052b60d0fc98 and will be in the soon-to-be-released v2.3.8.
> > 
> > I stopped 2.3.7, copied over the index files from the ramdisk into
> > the physical "realm" and restarted with a fresh 2.3.8. It probably
> > takes a few days to be absolutely sure.
> 
> So, in general the performance issues are gone.
> 
> But... 
> 
> I'm seeing odd hourly spikes almost every hour, on the hour.
> You might say: Well yes, that's a cronjob sending lots of mails. But
> it isn't. There's not more or less mail coming in at that very moment.
> 
> I suspect something in dovecot running every hour (DH key regeneration?)
> 
> -- 
> Ralf Hildebrandt

2.3.7 does not generate DH keys. It's been removed since 2.3.0

Is it possible for you to track and find out which process is causing the peak?

Aki