A short update: Interestingly the VM gained 77s (I had expected it _lost_ some time).
>>> "Ulrich Windl" <ulrich.wi...@rz.uni-regensburg.de> schrieb am 16.04.2014 um 09:18 in Nachricht <534e4add020000a100015...@gwsmtp1.uni-regensburg.de>: > Hello! > > I managed to migrate my Xen virtual machines live from one node to another. > Soe of the VMs have several GB of RAM with databases, so live migration takes > a while. However the typical user does not notice that the node migrated > (network connections stay alive). Unfortunately NTP seems to notice the time > migration took (77s in this case): > > ntpq -pn > remote refid st t when poll reach delay offset > jitter > ============================================================================ > == > *127.127.1.0 .LOCL. 10 l 3 64 377 0.000 0.000 > 0.001 > 132.199.176.18 192.53.103.108 2 u 180 512 377 0.239 -77753. > 41560.8 > 132.199.176.153 192.53.103.104 2 u 185 512 377 0.275 -77751. > 41560.1 > 172.20.16.1 132.199.176.153 3 u 191 512 377 0.378 -77753. > 41560.5 > 172.20.16.5 132.199.176.18 3 u 251 512 377 0.107 -77754. > 41560.2 > > So it thinks the other nodes are off by 77.7 seconds and sync to ist own > clock. > > Other VMs show simular results: > # ntpq -pn > remote refid st t when poll reach delay offset > jitter > ============================================================================ > == > *127.127.1.0 .LOCL. 10 l 6 64 377 0.000 0.000 > 0.001 > 132.199.176.18 192.53.103.108 2 u 582 1024 377 0.242 -78361. > 78359.9 > 132.199.176.153 192.53.103.104 2 u 546 1024 377 0.521 -78360. > 78360.1 > > # ntpq -pn > remote refid st t when poll reach delay offset > jitter > ============================================================================ > == > *127.127.1.0 .LOCL. 10 l 64 64 377 0.000 0.000 > 0.001 > 132.199.176.18 192.53.103.108 2 u 653 1024 377 0.326 -77837. > 77836.7 > 132.199.176.153 192.53.103.104 2 u 969 1024 377 0.453 -77835. > 77835.8 > 172.20.16.1 132.199.176.153 3 u 971 1024 377 4.937 -77837. > 77834.5 > 172.20.16.5 132.199.176.153 3 u 966 1024 377 6.283 -3.295 > 77836.9 > > As it turn out, the time in the VMs is actually wrong after migration: > # ntpq -pn > remote refid st t when poll reach delay offset > jitter > ============================================================================ > == > 127.127.1.0 .LOCL. 10 l 51 64 377 0.000 0.000 > 0.001 > +132.199.176.18 192.53.103.108 2 u 71 1024 377 0.362 -77840. > 2.573 > +132.199.176.153 192.53.103.104 2 u 386 1024 377 0.506 -77838. > 2.834 > *172.20.16.1 132.199.176.153 3 u 391 1024 377 4.140 -77840. > 2.744 > +172.20.16.5 132.199.176.18 3 u 386 1024 377 3.767 -77841. > 1.409 > > If I want to continue to use NTP, what are the recommendations? > > Regards, > Ulrich > > > _______________________________________________ > Linux-HA mailing list > Linux-HA@lists.linux-ha.org > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems _______________________________________________ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
