[ntp:questions] avoiding large steps (on time island)

seanjlangford at gmail.com seanjlangford at gmail.com
Thu May 17 15:51:01 UTC 2007


I'm having some trouble with a 'time island' type configuration;  I
have a number of ntp clients connecting to one ntp server using its
local clock driver (127.127.1.0).  This network is isolated from the
rest of the world, and for this application, having universally
correct time is far less important than having 'node-relative'
accurate time.  I have a problem scenario where the client starts
*before* the server and misses the opportunity to do the one time sync
to the server (ntp -g).  Then sometime after the server boots, the
clients clocks make large steps to correct the difference (with a
'time reset' ntp log message).   This is causing hangs in our client
application software as it uses software timers.  Is there a way to
limit the size of a step? or spread it out over time more slowly?  I
am aware of the -x flag, but would rather to continue to step, but in
smaller sizes.

Cheers

Sean

Client config:

tinker panic 0
logfile /var/log/ntpd.log
driftfile /var/lib/ntp/drift
server 192.168.2.163 prefer
fudge 192.168.2.163

Server config:

logfile /var/log/ntpd.log
driftfile /var/lib/ntp/drift
server  127.127.1.0 iburst minpoll 4
fudge 127.127.1.0 stratum 10 prefer




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