On 11/11/2010 06:41 PM, Jobst Schmalenbach wrote:
Hi.
I run peridocally (from cron) on all of my machines
30 * * * * root /sbin/hwclock --systohc
All of those machines in question take their time via NTP from the same local server, and that server gets its time from a ntp pool.
Now I had to reboot a couple of them two days ago and to my surprise all had problems with the time upon booting.
Here are the important files:
[root@XXXXXX ~] #>l /etc/adjtime 0.001687 1289518202 0.000000 1289518202 LOCAL
[root@XXXXXXX ~] #>l /etc/sysconfig/clock ZONE="Australia/Melbourne" UTC=false ARC=false
So from my understanding the hwclock should contain the local time.
[root@XXXXXX ~] #>date Fri Nov 12 11:26:23 EST 2010 [root@XXXXXX ~] #>hwclock Fri 12 Nov 2010 11:26:42 EST -0.167976 seconds [root@XXXXXX ~] #>
However on boot I get the following:
Nov 10 19:08:37 XXXXXX syslogd 1.4.1: restart. Nov 10 19:08:37 XXXXXX kernel: klogd 1.4.1, log source = /proc/kmsg started. Nov 10 19:08:37 XXXXXX kernel: Linux version 2.6.18-164.11.1.el5 (mockbuild@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4. 1.2-46)) #1 SMP Wed Jan 20 07:32:21 EST 2010 Nov 10 19:08:37 XXXXXX kernel: Command line: ro root=/dev/sda2 vga=791 Nov 10 19:08:37 XXXXXX kernel: BIOS-provided physical RAM map: ... ... Nov 10 19:08:51 XXXXXX kernel: IPv6 over IPv4 tunneling driver Nov 10 08:08:52 XXXXXX ntpdate[2464]: step time server 192.168.1.1 offset -39599.950905 sec Nov 10 08:08:52 XXXXXX xinetd[2447]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.
and off course dovecot falls over too "Time just moved backwards by 39599 seconds."
Now, 39600s is 11 hours, which is (inc DST) *MY* offset from Greenwich.
So what am I doing wrong? The idea of running hwclock is to make sure that exactly the problem with dovecot does NOT occur, and ntp does not have a coughing fit when the hardware clock is not close to the correct time upon booting. The last time I booted some of those machine was more than 200 days ago, so the hwclock will be skewed if I do not update it.
By any chance is /etc/localtime a symlink to a file system that is not mounted early in the boot process? That's why /etc/localtime is normally a _copy_ of the appropriate zoneinfo file.