index corruption weirdness

[Kelsey Cummings]

On 10/10/18 7:26 AM, Aki Tuomi wrote:
>> Are you saying that there is a bug in this version that affects RHEL 7.5
>> but not RHEL 6 or just use the newest version and maybe the problem goes
>> away?
> 
> We have very limited interest in figuring out problems with (very) old
> dovecot versions. At minimum you need to show this problem with 2.2.36
> or 2.3.2.1.
> 
> A thing you should make sure is that you are not accessing the user with
> two different servers concurrently.

The directors appear to be working fine so, no, users aren't hitting
multiple back end servers.

To be clear, we don't suspect Dovecot as much - our deployment had been
stable for years - but rather behavior changes between the RHEL6 and
RHLE7 environment, particularly with regards to NFSv3.  But we've have
been at a loss to find a smoking gun.

For various reasons achieving stability (again) on the current version
is very important while we continue to plan Dovecot and storage backend
upgrades.  Corruption leading to crashes is very infrequent percentage
wise but it's enough to negatively impact performance and impact users
-- out of 5+ million sessions/day we're seeing ~5 instances whereas on 6
it would have been one every few months.

Has anyone else experienced any NFS/locking issues transitioning from
RHEL6 to 7 with Netapp storage?  Grasping at straws - perhaps compiler
and/or system library issues interacting with Dovecot?

-K