progress, i think. thanks to all for comments.
referencing,
http://www.novell.com/communities/node/8629/time-synchronization-xen-setup http://www.linux.org.za/Lists-Archives/glug-tech-0905/msg00271.html http://www.gossamer-threads.com/lists/linux/kernel/1039416
i've decoupled DomU's time service from Dom0, @ both Dom0 & DomU
cat /proc/sys/xen/independent_wallclock
1checking available kernel clocksources,
cat /sys/devices/system/clocksource/clocksource0/available_clocksource
xen jiffies@ Dom0's /boot/grum/menu.lst, i've added,
module /vmlinuz-xen ... clocksource=jiffies ...and, at DomU's .cfg in Dom0,
extra = '... clocksource=jiffies ...'verifying in both Dom0 & DomU, i've
cat /sys/devices/system/clocksource/clocksource0/current_clocksource
jiffiesi've removed any pool servers, specifying local/regional Stratum 2/1 server, instead. both DomU & Dom0 have, atm,
cat /etc/ntp.conf
restrict default nomodify notrap noquery
restrict 127.0.0.1
restrict 192.168.1.0 mask 255.255.255.0 notrust nomodify notrap
server ac-ntp0.net.cmu.edu iburst
server ac-ntp1.net.cmu.edu iburst
server ac-ntp2.net.cmu.edu iburst
server clock.sjc.he.net iburst
driftfile /var/lib/ntp/drift/ntp.drift
logfile /var/log/ntpd/ntp.log
statsdir /var/log/ntpd/ # directory for statistics files
filegen peerstats file peerstats type day enable
filegen loopstats file loopstats type day enable
filegen clockstats file clockstats type day enableand ntp is running,
ps ax | grep ntp
13012 ? S<s 0:00 /usr/sbin/ntpd -p /var/run/ntp/ntpd.pid-g -u ntp:ntp -I eth0 -i /var/lib/ntp -c /etc/ntp.conf
after a few minutes, i've got time sync @ Stratum 2/3,
@ Dom0,
ntpq -p -c rv
assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,
version="ntpd 4.2.4p6@1.1549-o Fri May 8 08:40:54 UTC 2009 (1)",
processor="x86_64", system="Linux/2.6.27.29-0.1-xen", leap=00,-> stratum=2, precision=-8, rootdelay=18.717, rootdispersion=1077.662, peer=35633, refid=216.218.254.202, reftime=ce7605a0.6d9086a4 Tue, Oct 6 2009 11:06:24.427, poll=6, clock=ce7606ac.ba2a0e0c Tue, Oct 6 2009 11:10:52.727, state=2, offset=-119.499, frequency=-37.025, jitter=455.226, noise=42.407, stability=0.040, tai=0 remote refid st t when poll reach delay offset jitter ============================================================================== +AC-NTP0.net.cmu 128.237.148.140 2 u 12 64 37 99.147 -669.34 452.011 +AC-NTP1.net.cmu 128.237.148.132 2 u 13 64 37 95.951 -667.96 454.264 +AC-NTP2.net.cmu 128.237.148.132 2 u 5 64 35 89.923 -688.34 496.274 *clock.sjc.he.ne .CDMA. 1 u 15 64 37 15.566 -673.46 455.158 ntpdc -c kerninfo pll offset: -0.09179 s pll frequency: -37.025 ppm maximum error: 0.135195 s estimated error: 0.042407 s status: 0001 pll pll time constant: 6 precision: 1e-06 s frequency tolerance: 500 ppm
@ DomU,
ntpq -p -c rv
assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,
version="ntpd 4.2.4p6@1.1549-o Fri May 8 08:40:54 UTC 2009 (1)",
processor="x86_64", system="Linux/2.6.27.29-0.1-xen", leap=00,-> stratum=3, precision=-8, rootdelay=98.154, rootdispersion=357.033, peer=50391, refid=216.218.254.202, reftime=ce7605c4.85c9d4d7 Tue, Oct 6 2009 11:07:00.522, poll=6, clock=ce7606b2.b01ba2b4 Tue, Oct 6 2009 11:10:58.687, state=2, offset=-102.003, frequency=-2.249, jitter=367.417, noise=36.248, stability=0.409, tai=0 remote refid st t when poll reach delay offset jitter ============================================================================== +AC-NTP0.net.cmu 128.237.148.140 2 u 35 64 17 91.744 -557.29 359.884 +AC-NTP1.net.cmu 128.237.148.140 2 u 37 64 17 96.365 -548.70 355.430 +AC-NTP2.net.cmu 128.237.148.132 2 u 54 64 17 98.517 -509.63 363.221 *clock.sjc.he.ne .CDMA. 1 u 37 64 17 22.907 -553.69 366.781 ntpdc -c kerninfo pll offset: -0.080367 s pll frequency: -2.249 ppm maximum error: 0.12257 s estimated error: 0.036248 s status: 0001 pll pll time constant: 6 precision: 1e-06 s frequency tolerance: 500 ppm
with this setup,
service dovecot-custom restart
Stopping dovecot done
Starting dovecot ILoading modules from directory: /usr/local/lib/dovecot/imap
IModule loaded: /usr/local/lib/dovecot/imap/lib01_acl_plugin.so
IModule loaded: /usr/local/lib/dovecot/imap/lib10_quota_plugin.so
IModule loaded: /usr/local/lib/dovecot/imap/lib11_imap_quota_plugin.so
IEffective uid=65534, gid=65533, home=/tmp
IQuota root: name=storage=10240 backend=maildir args=
doneand watching,
tail -f /var/log/dovecot/*logthe problem appears again,
...
Oct 06 10:58:37 auth(default): Info: new auth connection: pid=17797
Oct 06 10:58:37 auth(default): Info: new auth connection: pid=17798
Oct 06 10:58:37 auth(default): Info: new auth connection: pid=17799
Oct 06 11:06:23 dovecot: Error: Time just moved backwards by 1seconds. I'll sleep now until we're back in present. http://wiki.dovecot.org/TimeMovedBackwards
and, checking syslog,
...
Oct 6 11:06:22 mx ntpd[17697]: time reset -2.203456 s
Oct 6 11:07:00 mx ntpd[17697]: synchronized to 128.2.1.22, stratum 2
Oct 6 11:08:11 mx ntpd[17697]: synchronized to 216.218.254.202, stratum 1so it _looks_ like a reset was done, then stratum 2 & 1 sync were achived.
as of,
date
Tue Oct 6 11:20:58 PDT 2009there have been no further, related errors/entries in either dovecot logs or syslog.
fixed? improved? unclear ....