[Dovecot] "Time just moved backwards" in Dovecot in a Xen DomU

[PGNet Dev]

> The wiki page also suggests clockspeed or chrony if ntpd can't seem to
> keep the time correct. Maybe one of those helps. Hmm. The Chrony's web
> site seems to be gone, wonder if it has a new one somewhere..

sure, but with the _widespread_ use of ntp(d), this bears investigation.

and, unfortunately, at least on opensuse, both

  http://software.opensuse.org/search?q=chrony
  http://software.opensuse.org/search?q=clockspeed

return empty.  which means that a manual intervention -- certainly
doable, but hardly 'mainstream' -- will be required.

atm, anyway, trying another approach. reading @,

	http://lists.ntp.isc.org/pipermail/questions/2009-August/024110.html

changing,

@ Dom0
	echo "1"       > /proc/sys/xen/independent_wallclock
	echo "jiffies" >
/sys/devices/system/clocksource/clocksource0/current_clocksource

@ DomU
	echo "0"   > /proc/sys/xen/independent_wallclock
	echo "xen" > /sys/devices/system/clocksource/clocksource0/current_clocksource

i.e., Dom0 _not_ using xen timekeeping, rather 'traditional' ntpd
service, and DomU (running Dovecot) depending on DomU _using_ the xen
timesource drivers.

then, @ DomU

	service ntp stop
	service dovecot-custom restart

& watching,

	tail -f /var/log/dovecot/*log /var/log/messages

returns,

	Oct 06 11:41:53 dovecot: Info: Dovecot v1.2.6 starting up (core dumps disabled)
	Oct 06 11:41:53 auth(default): Info: passwd-file
/data/mail/Data/USERS/imap_user_file: Read 2 users
	Oct 06 11:41:54 auth(default): Info: new auth connection: pid=18001
	Oct 06 11:41:54 auth(default): Info: new auth connection: pid=18003
	Oct 06 11:41:54 auth(default): Info: new auth connection: pid=18002
	...

with this approach, at least as of

     Tue Oct  6 12:05:40 PDT 2009

no further errors.  a 'new record' at 24 minutes ...  encouraging, but
will keep an eye on it for awhile.