dovecot.index.log: duplicate transaction log sequence (3)

[Aki Tuomi]

> 
>  
> Hello,
> 
> I am running Dovecot 2.3.5.1 on OpenBSD 6.5 with RainLoop as IMAP webmail client and just noticed the following error messages about duplicate transaction log sequences in the index log:
> 
> Jul 01 13:15:58 Error: imap(<REMOVED_EMAIL1>)<21324><TVSmwJyMd0C5D+Vb>: Transaction log /var/vmail/<REMOVED_DOMAIN>/<REMOVED_EMAIL1>/dovecot.index.log: duplicate transaction log sequence (3)
> Jul 02 16:33:35 Error: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: Transaction log /var/vmail/<REMOVED_DOMAIN>/<REMOVED_EMAIL2>/dovecot.list.index.log: duplicate transaction log sequence (2)
> Jul 02 16:33:35 Panic: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: file mail-index-write.c: line 137 (mail_index_write): assertion failed: (file->hdr.prev_file_seq == hdr->log_file_seq)
> Jul 02 16:33:35 Fatal: imap(<REMOVED_EMAIL2>)<6812><gn4yobOMJlW5D+Vb>: master: service(imap): child 6812 killed with signal 6 (core not dumped - https://dovecot.org/bugreport.html#coredumps - set service imap { drop_priv_before_exec=yes })
> 
> Could this problem occur because I am using a Linux NFS server to store all the mails mounted under /var/mail ?
> 
> Any hints what I can do to avoid these error messages?
> 
> Thank you in advance.
> 
> Best regards,
> Mabi

Are you by chance accessing mails using two different dovecot instances? This is not supported to be done concurrently, you need to use some sort of solution, such as dovecot director, to ensure user lands to one backend at a time.

Aki