[Dovecot] Dovecot service not responding after about a week of uptime

[Matthieu]

Hello,

I am running a dovecot 2.1.13 server and lately it stops responding 
after about a week of uptime. Simply restarting the dovecot service 
solves the issue.

I tried to look a bit in my maillog file but did not find anything 
obvious. During the time when the server is not responding I can still 
see  imap-login entries from the connection attempt by my email client. 
Any help about how to diagnose the problem would be appreciated.

Thanks,

Matthieu