Re: "clocks not synchronized" warning message

[Thomas Mueller <thomas@chaschperli.ch>]

Am Thu, 08 Jul 2010 07:53:00 -0700 schrieb Sage Weil:

> On Thu, 8 Jul 2010, Thomas Mueller wrote:
> 
>> Am Thu, 08 Jul 2010 16:19:28 +0200 schrieb Wido den Hollander:
>> 
>> > Hi,
>> > 
>> > I'm experiencing the same. The default "mon lease wiggle room" is set
>> > t .001, which gives the messages in my setup.
>> 
>> this is what I just found too - in unstable the default is now 0.010.
>> with 0.5 the message was still there. with 1.0 it was away.
>> 
>> I think 0.010 is still a bit small for a system not connected to a
>> atomic clock? :)
> 
> How about .5 seconds?  We sync our machines to a local ntp server, so
> the clocks get really close (sub-ms).  I forget that NTP isn't so
> accurate over a WAN.
> 
> The issue is that the monitor leases and timeouts are something like 2
> seconds (so that failures/unavailability) are detected quickly, so the
> tolerable clock drift can't get too close to that.
> 
> sage

ok, if this is the problem, then I would also recommend running an ntp 
daemon (not ntpdate) on every node. A running ntpd will manage the 
timesource to be in sync. 

If anyone likes to run an mds/mon on a VM I expect problems - virtualized 
clocksources are far less stable (my experience).

- Thomas