Dovecot Director upgrade from 2.2 to 2.3

Hi,

I have a setup with 3 Dovecot Director v2.2.36 and director_consistent_hashing = yes ;-)

Now I would like to upgrade to 2.3.7, first only Director and after also Backend.

Can works fine a ring of director with mixed 2.2 and 2.3 version?

Mi idea is to setup a new Director server with 2.3, stop one server with 2.2 and insert the new 2.3 in the current ring to check if works fine.

If all works fine I will replace all Director 2.2 with 2.3 version.

There's no known reason why it wouldn't work. But be prepared in case there is an unknown reason.

Alessio Cecchi

22 Jul 22 Jul

7:45 p.m.

Il 18/07/19 21:42, Timo Sirainen ha scritto:

...

On 18 Jul 2019, at 11.44, Alessio Cecchi via dovecot mailto:dovecot@dovecot.org> wrote:

...
Hi,

I have a setup with 3 Dovecot Director v2.2.36 and director_consistent_hashing = yes ;-)

Now I would like to upgrade to 2.3.7, first only Director and after also Backend.

Can works fine a ring of director with mixed 2.2 and 2.3 version?

Mi idea is to setup a new Director server with 2.3, stop one server with 2.2 and insert the new 2.3 in the current ring to check if works fine.

If all works fine I will replace all Director 2.2 with 2.3 version.

There's no known reason why it wouldn't work. But be prepared in case there is an unknown reason.

Hi,

one server of the ring is now running Dovecot 2.3.7 and works fine with the others Dovecot 2.2 since 3 days.

I notice only that the load avarage of this CentOS 7 server is higher compared with CentOS 6 and Dovecot 2.2, but I don't know if is related to the new operating system or Dovecot (hardware is the same).

If I do not encounter problems in the next days I will also update the other Directors.

Thanks

-- Alessio Cecchi Postmaster @ http://www.qboxmail.it https://www.linkedin.com/in/alessice

Timo Sirainen

7:49 p.m.

On 22 Jul 2019, at 17.45, Alessio Cecchi alessio@skye.it wrote:

...

one server of the ring is now running Dovecot 2.3.7 and works fine with the others Dovecot 2.2 since 3 days. I notice only that the load avarage of this CentOS 7 server is higher compared with CentOS 6 and Dovecot 2.2, but I don't know if is related to the new operating system or Dovecot (hardware is the same).

How much higher? Can you check the individual dovecot processes' CPU usage? I guess mainly director, imap-login and pop3-login. The director code should be pretty much the same though.

The SSL code in login processes changed in v2.3, so I wonder if the new code has some performance issues.

Alessio Cecchi

31 Jul 31 Jul

3:41 p.m.

Hi Timo,

here you can see two images with the load average and CPU usage with Dovecot 2.2 (Centos 6) and 2.3 (Centos 7) on the same hardware and same configuration:

https://imgur.com/a/1hsItlc

Load average increment is relevant but CPU usage is similar.

Il 22/07/19 18:49, Timo Sirainen ha scritto:

...

On 22 Jul 2019, at 17.45, Alessio Cecchi mailto:alessio@skye.it> wrote:

...
one server of the ring is now running Dovecot 2.3.7 and works fine with the others Dovecot 2.2 since 3 days.

I notice only that the load avarage of this CentOS 7 server is higher compared with CentOS 6 and Dovecot 2.2, but I don't know if is related to the new operating system or Dovecot (hardware is the same).

How much higher? Can you check the individual dovecot processes' CPU usage? I guess mainly director, imap-login and pop3-login. The director code should be pretty much the same though.

The SSL code in login processes changed in v2.3, so I wonder if the new code has some performance issues.

-- Alessio Cecchi Postmaster @ http://www.qboxmail.it https://www.linkedin.com/in/alessice

Timo Sirainen

1 Aug 1 Aug

4:46 p.m.

On 31 Jul 2019, at 15.41, Alessio Cecchi via dovecot dovecot@dovecot.org wrote:

...

Hi Timo,

here you can see two images with the load average and CPU usage with Dovecot 2.2 (Centos 6) and 2.3 (Centos 7) on the same hardware and same configuration:

https://imgur.com/a/1hsItlc https://imgur.com/a/1hsItlc Load average increment is relevant but CPU usage is similar.

Load average changes can be rather difficult to debug if it's not because of any CPU usages or disk IO, and in your graphs those hadn't really changed. One more possibility could be to look at context switches, but do you have those from before the upgrade? (sar database?) Also since you changed CentOS 6 -> 7 it could be possible that it has nothing to do with Dovecot at all.

Alessio Cecchi

10 Sep 10 Sep

5:14 p.m.

Il 22/07/19 18:49, Timo Sirainen ha scritto:

...

On 22 Jul 2019, at 17.45, Alessio Cecchi mailto:alessio@skye.it> wrote:

...
one server of the ring is now running Dovecot 2.3.7 and works fine with the others Dovecot 2.2 since 3 days.

I notice only that the load avarage of this CentOS 7 server is higher compared with CentOS 6 and Dovecot 2.2, but I don't know if is related to the new operating system or Dovecot (hardware is the same).

How much higher? Can you check the individual dovecot processes' CPU usage? I guess mainly director, imap-login and pop3-login. The director code should be pretty much the same though.

The SSL code in login processes changed in v2.3, so I wonder if the new code has some performance issues.

Just for info,

I have upgraded all directors ring to Dovecot 2.3 but maintaining CentOS 6 and the load average is the same, so the increase of load during the first upgrade was caused by CentOS 7, not by Dovecot 2.3.

Ciao

-- Alessio Cecchi Postmaster @ http://www.qboxmail.it https://www.linkedin.com/in/alessice

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Alessio Cecchi
Timo Sirainen