index corruption weirdness

[Aki Tuomi]

On 09.10.2018 22:16, William Taylor wrote:
> We have started seeing index corruption ever since we upgraded (we 
> believe) our imap servers from SL6 to Centos 7. Mail/Indexes are stored 
> on Netapps mounted via NFS. We have 2 lvs servers running surealived in 
> dr/wlc, 2 directors and 6 backend imap/pop servers.
>
> Most of the core dumps I've looked at for different users are like 
> "Backtrace 2" with some variations on folder path.
>
> This latest crash (Backtrace 1) is different from others I've seen.
> It is also leaving 0byte files in the users .Drafts/tmp folder.
>
> # ls -s /var/spool/mail/15/00/user1/.Drafts/tmp | awk '{print $1}'  
>   |sort | uniq -c
>    9692 0
>       1 218600
>
> I believe the number of cores here is different from the number of tmp 
> files because this is when we moved the user to our debug server so we
> could get the core dumps.
> # ls -la /home/u/user1/core.* |wc -l                                   
>   8437
>
> Any help/insight would be greatly appreciated.
>
> Thanks,
>   William
>
>
> OS Info:
> CentOS Linux release 7.5.1804 (Core)
> 3.10.0-862.14.4.el7.x86_64
>
> NFS:
> # mount -t nfs |grep mail/15
> 172.16.255.14:/vol/vol1/mail/15 on /var/spool/mail/15 type nfs 
> (rw,nosuid,nodev,relatime,vers=3,rsize=32768,wsize=32768,namlen=255,hard,nordirplus,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=172.16.255.14,mountvers=3,mountport=4046,mountproto=udp,local_lock=none,addr=172.16.255.14)
>
> Dovecot Info:
> dovecot -n
> # 2.1.17: /etc/dovecot/dovecot.conf
>

Hi!

Thank you for your report, however, 2.1.17 is VERY old version of
dovecot and this problem is very likely fixed in a more recent version.

Aki