6 Sep
2011
6 Sep
'11
6:23 p.m.
Hi everyone,
Apologies if this is really not VPS-related, but I thought I'd post it
just in case it might be...
I maintain the clock on my VPS (running Debian Lenny) with ntpd however I
am having an occasional issue with it insofar that every couple of months
or so it is suddenly making a massive timeshift (-46 seconds in this
case):
Sep 6 12:29:29 targur ntpd[1412]: kernel time sync status change 4001
Sep 6 12:46:34 targur ntpd[1412]: kernel time sync status change 0001
Sep 6 13:55:40 targur ntpd[1412]: synchronized to 74.118.152.85, stratum 2
Sep 6 13:56:37 targur ntpd[1412]: no servers reachable
Sep 6 14:07:10 targur ntpd[1412]: synchronized to 80.85.129.103, stratum 2
Sep 6 14:07:52 targur ntpd[1412]: time reset -46.871472 s
Sep 6 14:07:57 targur ntpd[1412]: synchronized to 209.237.247.192, stratum 3
Sep 6 14:08:09 targur ntpd[1412]: synchronized to
2001:7b8:633:1:213:154:236:182, stratum 2
Sep 6 14:12:10 targur ntpd[1412]: synchronized to 80.85.129.103, stratum 2
Sep 6 14:18:40 targur ntpd[1412]: synchronized to
2001:7b8:633:1:213:154:236:182, stratum 2
Sep 6 14:22:51 targur ntpd[1412]: synchronized to 80.85.129.103, stratum 2
Sep 6 15:48:24 targur ntpd[1412]: kernel time sync status change 4001
Sep 6 16:05:27 targur ntpd[1412]: kernel time sync status change 0001
Sep 6 17:30:53 targur ntpd[1412]: kernel time sync status change 4001
Sep 6 17:47:56 targur ntpd[1412]: kernel time sync status change 0001
Sep 6 18:56:11 targur ntpd[1412]: synchronized to
2001:7b8:633:1:213:154:236:182, stratum 2
The servers listed in /etc/ntp.conf are:
server ntp0.sfo.bitfolk.com iburst
server ntp0.lon.bitfolk.com iburst
server ntp1.lon.bitfolk.com iburst
server 0.us.pool.ntp.org iburst
server 1.us.pool.ntp.org iburst
server 2.us.pool.ntp.org iburst
server 0.pool.ntp.org iburst
server 1.pool.ntp.org iburst
server 2.pool.ntp.org iburst
Whilst the clock seems to get back on track the problem is that my IMAP
server throws a wobbly and self-destructs:
Sep 6 14:07:52 targur dovecot: Time just moved backwards by 47 seconds.
This might cause a lot of problems, so I'll just kill myself now.
http://wiki.dovecot.org/TimeMovedBackwards
...which whilst only requiring a simple restart of Dovecot I still have to
spot that it has happened first.
I am aware that I can tweak ntpd to not attempt such large jumps however I
can't help be feel that doing this is treating the symptom rather than the
cause and so I am keen to find out what the real problem is (it also has
other drawbacks such a slowing down corrective action when actually
required).
Does anyone else have this problem? I could understand such large jumps
following a fresh boot, or after a manual clock change, but not when
running in steady state...
Regards,
Mathew