[ntp:questions] Tricking NTP's driftfile

Kevin Oberman oberman at es.net
Tue Jun 24 17:51:34 UTC 2008


> Date: Mon, 23 Jun 2008 18:11:18 -0400
> From: Steven <sed_facebook at vt.edu>
> Sender: questions-bounces+oberman=es.net at lists.ntp.org
> 
> 
> System Information:
> -------------------
> At work, I am configuring a system which consists of six servers (master,
> slave1, ... slave5) networked together but kept isolated from any external
> network.
> 
> The ONLY time requirement is that all the systems have the same time,
> which does NOT need to be accurate, just consistent.
> 
> All servers run RHEL4 and use ntp-4.2.0.a.20040617-6.el4.
> 
> All systems: (all files owned by root unless specified)
>   /etc/ntp.conf 644
>     server 127.127.1.0
>     server master # LINE NOT INCLUDED ON master
>     driftfile /var/lib/ntp/drift
>     broadcastdelay 0.08
> 
>  /etc/ntp           755
>  /etc/ntp/keys      600: Only commented lines
>  /etc/ntpservers    644: Default (redhat time servers)
>  /etc/step-tickers  644: slave: master, master: empty
>  /var/lib/ntp/drift 644 (ntp:ntp): 0.0
> 
> Problem:
> --------
> While the master goes through its synchronization routine (~10 mins),
> the slaves cannot obtain the time (see below).  Even after the master
> is responsive, the drift file is not written to.
> [root at slave1 ~]# ntpdate -d master
> ...
> 192.168.1.1: Server dropped: strata too high
> ...
> 23 Jun 17:28:33 ntpdate [3343]: no server suitable for synchronization found

OK. Why is it taking ~10 minutes to sync?  

This one I see fairly often and I don't understand it. My systems
typically are synced and available for use in <3 minutes.

Do you use iburst and -g? If so, that should get the master synced very
quickly and your clients should be able to start their own sync, also
using iburst.

I have not been following this thread, so this my already have been
discussed.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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