I had a similar problem on a different server that I fixed last night. Evidently it had a BIOS level feature that tried to modify the CPU clock rate, much like cpu-freq does within the kernel, and was doing so by messing with the system clock impacting the RTC. I was drifting all over the place until I found and disabled that feature (foxcon board, something like foxstep I believe is what it is called in BIOS). Not sure if your lenovo boards have that feature, but i know that some ASUS boards do. Jason www.cyborgworkshop.org Paul Heinlein wrote: > On Tue, 20 May 2008, Alfred von Campe wrote: > >> I have 30 identical Lenovo desktop systems running CentOS 5.1. On one >> of those systems the clock is running slow (5+ minutes from yesterday >> to this morning and another minute since this morning) despite the >> fact that NTP is running on all of them and they all have the exact >> same /etc/ntp.conf file (I compared the MD5 sums of that file on all >> the systems). Here is the output of "grep ntp /var/log messages" on >> the system with the problem since I restarted the NTP daemon earlier >> today: > > A slew of 5 min/24 hrs should be in the range of fixable. > >> May 20 11:35:38 hepdsw03 ntpd[31792]: frequency initialized 0.000 PPM >> from /var/lib/ntp/drift > > This is very suspect. Are there any SELinux or other log messages > suggesting that ntpd isn't able to write to its drift file? Your local > clock is definitely drifting, so a 0.000 value is bogus. It may indicate > that there's a disconnect between ntpd and the filesystem. > > I'd be interested in the output of "ntpdc -c kerninfo"; on most systems > the 'pll frequency' value is a close match to the figure in the drift file. > >> May 20 11:38:55 hepdsw03 ntpd[31792]: synchronized to LOCAL(0), >> stratum 10 >> May 20 11:38:55 hepdsw03 ntpd[31792]: kernel time sync disabled 0001 >> May 20 11:39:59 hepdsw03 ntpd[31792]: synchronized to 10.101.32.104, >> stratum 3 > > This is ungood. Sync-ing to local before your network time server means > that your machine doesn't want to believe your server -- and you should > see a "kernel time sync enabled" message once the machine has sync-ed > with the time server. > > You said the machines are identical. Could there be any variation in the > BIOS revision level or its settings? Sometimes ACPI stuff can mess up ntp. > > Also -- the log messages you provide have no "step time server" > reference. Do you have a valid /etc/ntp/step-tickers file? >