[Dovecot] May 05 07:20:21 imap: Warning: Time jumped forwards 16 seconds

[Noel]

On 5/6/2011 5:53 AM, Charles Marcus wrote:
> ntpdate, which causes large jumps, should only be used at 
> boot time
> BEFORE server processes are started, then ntp CLIENT keeps the systems
> clock in sync using tiny increments, usually less than a second.
>

No, ntpd adjusts the clock frequency to keep the system in 
close sync with a reliable time source.  To work properly, 
ntpd expects to be a long-running process so it can figure out 
the local clock drift and properly adjust it.

Anyway, drifting off topic here.  Bottom line is that your 
server needs stable time, which ntpd can provide.  Exceptions 
are virtual machines, which have their own time tools, and 
"personal" devices that sleep/resume frequently, AFAIK no 
reliable solution for these.

   -- Noel Jones