index corruption weirdness

[William Taylor]

On Wed, Oct 10, 2018 at 09:37:46AM +0300, Aki Tuomi wrote:
> 
> 
> 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
> 

I realize it is an older release.

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?