[ext] 2.3.7 slower than 2.3.6?

Ralf Hildebrandt Ralf.Hildebrandt at charite.de
Wed Jul 17 12:47:59 EEST 2019

> > All of the data is an /dev/sda1
> What filesystem is this?

> I did a bunch of testing, and after initially thinking I saw an
> increase it was just due to bad testing because the new TCP_NODELAY
> changes allowed imaptest to do more work. So I can't see that there is
> any disk IO difference.
> There are a few intentional changes to lib-index and also mdbox
> code. One of those is that dovecot.index.cache files are being
> recreated more often now. In some cases they were wasting a lot of
> disk space because expunged mails hadn't been removed from them. I
> guess it's a possibility that all the disk IO was because in your
> system Dovecot started recreating all those files at the same time.
> Maybe you could try upgrading again during slower hours and see if the
> disk IO normalizes after a while?

Still running 2.3.7. 

Looking at the disk IO graphs today's IO usage looks OK!

I restarted dovecot yesterday after fixing the FTS settings:
Jul 16 10:14:45 mail-cbf dovecot: master: Dovecot v2.3.7 (494d20bdc) starting up for imap, lmtp (core dumps disabled)

after that I saw quite a bit of IO on sda1 (a bit of data read, lot of write),
which subsided at11:30

After that diskio was low, up to the present day.

Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | https://www.charite.de

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