On Tue, May 07, 2019 at 09:42:38AM +0200, lists wrote:
But we wonder why can "chronyc cources" would say we are synced, when in
fact we are a whole scond off. (claim from ceph, but verified by looking at
"top" command in terminal windows: the ceph machines WERE not synced)
chronyc sources doesn't really say if/how well the clock is
synchronized. It shows which sources are reachable, selected and the
last measured offset with error estimates and how long ago it was made
(that would be a hint that it stopped making new measurements).
chronyc tracking is more important for monitoring the local clock.
There is the root delay and root dispersion, which together make an
upper bound for the error of the clock.
If the sources are specified with the offline and iburst options, and
there is nothing to switch them to online, there will be only few
measurements on start, which will correct the initial offset of the
clock, but it will not really be synchronized. The root dispersion
will grow very quickly.