[Dovecot] dovecot and ntp: Fatal: Time just moved backwards

[Scott Haneda]

Sorry for the top post and lack of snipping this email down, I'm using  
a mobile phone.

Can you explain why the system clock gets so far out of time? I  
certainly struggle with crime drifting even on an always network  
connected machine, but I'm not understanding why your machine can not  
maintain time within a very small margin of error even if turned off  
for months.
-- 
Scott
Iphone says hello.

On Jun 6, 2009, at 11:19 AM, Arno Wald <arno.wald at netcologne.de> wrote:

> Hallo,
>
> I am running dovecot on a PC (a workstation) to have a mail client  
> independent storage for my mails. Now I would like to have the  
> system clock set correctly by using ntpd or ntpdate (using debian/ 
> sid).
>
> The problem is, that the PC is not online at boot time, but is set  
> online on demand manually using "pon" to start the pppd later. So  
> ntpd cannot sync the time on boot time before dovecot gets started.
>
> First I was using ntpdate that was started in ppp's if.up.d/  
> directory. This tool does set the time very hard instead of just  
> slightly shifting some milliseconds. So dovecot did stop itself,  
> reporting:
>
> "Fatal: Time just moved backwards by 118 seconds. This might cause a  
> lot of problems, so I'll just kill myself now."
>
> So I have tried ntpd as I thought it shifts the time in smaller time  
> deltas. But this takes much time (several seconds) when booting,  
> giving up on all configured servers, because they are not reachable  
> when booting (as going online later manually). This turns off ntp  
> functionality because ntpd does think that all servers are  
> unreachable for ever. (I have tried a command "dynamic" in ntp.conf  
> but this did not change anything and ntpd reports it to be obsolete.)
>
> My idea now is to not start ntpd on system boot, but only on if-up.  
> But this brings up the same fatal error of dovecot as ntpd seems to  
> hardly set the time, too. The only idea I have left is to stop  
> dovecot, start ntpd and then start dovecot again on if-up.
>
> Is there a more elegant way to use dovecot and ntpd on a manually  
> dialed in PC?
>
> Thanks,
> Arno