> -----Original Message----- > From: centos-bounces at centos.org > [mailto:centos-bounces at centos.org] On Behalf Of Simon Billis > Sent: Thursday, August 12, 2010 7:36 > To: 'CentOS mailing list' > Subject: Re: [CentOS] Date drift and ntpd > > Jason Pyeron sent a missive on 2010-08-12: > > > We have a local time server and all of our machines are > pointed at it > > for the time. > > > > How can the clock drift by a day and a half? > > > > [root at devserver21 ~]# date > > Fri Aug 13 14:43:29 EDT 2010 > > [root at devserver21 ~]# rdate -s 192.168.1.67 > > [root at devserver21 ~]# date > > Thu Aug 12 07:02:39 EDT 2010 > > [root at devserver21 ~]# cat /etc/ntp.conf | grep -v ^# | grep -v ^$ > > restrict default nomodify notrap noquery restrict 127.0.0.1 server > > 192.168.1.67 server 192.168.1.66 server 192.168.1.65 > > server 127.127.1.0 # local clock > > fudge 127.127.1.0 stratum 10 > > driftfile /var/lib/ntp/drift > > broadcastdelay 0.008 > > keys /etc/ntp/keys > > > > > > Hi, > > It is unlikely that the machine in question drifted forward > in time if ntpd was running. Have a look at the logs > /var/log/messages it should contain the ntpd log messages [root at devserver21 ~]# grep ntpd /var/log/messages </snip> Jul 28 20:34:41 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 21:08:00 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 28 21:08:00 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:08:11 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 28 21:24:58 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 21:41:26 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 28 21:42:16 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 28 21:42:16 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:42:34 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:43:37 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:44:41 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:45:44 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:46:45 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:47:50 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:48:55 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:49:57 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:50:59 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:52:03 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:53:05 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:54:06 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:55:10 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:56:13 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:57:16 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:58:20 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 21:59:23 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:00:28 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:01:32 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:02:35 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:03:38 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:04:41 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:05:44 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:06:49 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:07:53 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:08:57 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:10:00 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:11:03 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:12:07 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:13:13 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:14:17 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:15:11 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 28 22:31:41 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 28 22:31:41 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 22:31:59 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 23:05:10 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 28 23:05:10 devserver21 ntpd[3475]: frequency error -512 PPM exceeds tolerance 500 PPM Jul 28 23:06:05 devserver21 ntpd[3475]: time reset +0.554019 s Jul 28 23:10:14 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 28 23:17:36 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 28 23:20:46 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 28 23:22:52 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 23:33:28 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 23:34:37 devserver21 ntpd[3475]: time reset -0.866445 s Jul 28 23:38:49 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 28 23:43:01 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 28 23:44:03 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 00:00:57 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 00:25:53 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 00:41:48 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 00:42:45 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 00:42:44 devserver21 ntpd[3475]: time reset -0.922073 s Jul 29 00:46:58 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 00:57:27 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 01:07:55 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 01:57:05 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 02:13:48 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 02:13:52 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 02:30:31 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 03:03:59 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 03:04:00 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 03:04:00 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 03:37:21 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 04:10:46 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 04:44:06 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 05:00:48 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 05:00:52 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 05:17:30 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 05:34:13 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 06:24:16 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 06:40:59 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 07:30:59 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 07:47:42 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 07:47:53 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 08:04:23 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 08:37:47 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 08:37:58 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 09:11:03 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 09:27:43 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 09:27:44 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 09:28:00 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 10:17:40 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 10:50:57 devserver21 ntpd[3475]: time reset -1.638135 s Jul 29 10:55:08 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 10:58:17 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 10:59:16 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 11:07:41 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 11:11:57 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 11:13:58 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 11:19:00 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 11:21:19 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 11:29:46 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 11:39:57 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 11:41:56 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 11:44:23 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 12:03:03 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 12:05:19 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 12:23:28 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 12:27:48 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 13:34:13 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 13:51:08 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 14:03:08 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 14:07:42 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 14:23:56 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 14:40:29 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 14:57:07 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 14:57:27 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 15:13:40 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 15:14:01 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 15:26:05 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 15:59:17 devserver21 ntpd[3475]: time reset -1.599691 s Jul 29 16:03:31 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 16:05:38 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 16:08:46 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 16:11:55 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 16:12:59 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 16:15:00 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 16:28:32 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 16:41:10 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 16:57:35 devserver21 ntpd[3475]: synchronized to 192.168.1.66, stratum 3 Jul 29 17:23:57 devserver21 ntpd[3475]: synchronized to 192.168.1.67, stratum 3 Jul 29 17:24:59 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Jul 29 17:30:46 devserver21 ntpd[3475]: synchronized to 192.168.1.65, stratum 3 Jul 29 17:47:24 devserver21 ntpd[3475]: synchronized to LOCAL(0), stratum 10 Aug 12 22:48:29 devserver21 ntpd[3475]: sendto(192.168.1.66): Operation not permitted [root at devserver21 ~]# uptime 08:10:19 up 164 days, 9:56, 2 users, load average: 0.20, 0.54, 0.81 [root at devserver21 ~]# > which will help you determine what happened to the time. > Also check that ntpd is running with: > > "service ntpd status" and also "chkconfig ntpd --list" will > show the startup position of ntpd > It is/was up. -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- - - - Jason Pyeron PD Inc. http://www.pdinc.us - - Principal Consultant 10 West 24th Street #100 - - +1 (443) 269-1555 x333 Baltimore, Maryland 21218 - - - -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- This message is copyright PD Inc, subject to license 20080407P00.