topic Re: Hwclock does not maintain correct time in Operating System - Linux

Hwclock does not maintain correct time

ScottLClement — Thu, 04 Jan 2007 13:01:12 GMT

I have a DL580 itanium server running redhat linux RHEL 4. THe hardware clock floats drastically. After 19 days of uptime it was 2days + behind. Does anyone have any ideas why this is?

Re: Hwclock does not maintain correct time

Ivan Ferreira — Thu, 04 Jan 2007 13:06:45 GMT

Hello, please see this thread and try the suggestions there.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=999210

Re: Hwclock does not maintain correct time

Steven E. Protter — Thu, 04 Jan 2007 16:09:43 GMT

Shalom,

Congratulations, you have discovered that computers can't tell time.

I would suggest you set up ntp and ignore the hardware clock.

If its really interfering with system operation and ntp can't sync it, have the system board replaced. Your results are pretty bad but I've seen worse.

SEP

Re: Hwclock does not maintain correct time

ScottLClement — Thu, 04 Jan 2007 17:18:06 GMT

We have set up ntp but we are having problems getting out the correct nic to hit the outside time server. We have 3 nics on 3 different subnets and it fails to get out yet from telnet window we can ping and nslookup the time server just fine.

Re: Hwclock does not maintain correct time

Morten Lange — Sun, 07 Jan 2007 08:14:13 GMT

Hi,

Regarding connectivity to the NTP server, you should know that NTP uses port 123 udp _and_ tcp.

When you say telnet, are you telnetting to port 123 on the ntp server ?
To test 123 udp I think you could use nmap.
Is there a firewall on the route between the to boxes or perhaps iptables or something running on your linux box ?

Then there is the question of whether you are going out through the right NIC. Have you double-checked the routing tables ?

Best Regards,
Morten

Re: Hwclock does not maintain correct time

George Liu_4 — Mon, 08 Jan 2007 14:40:53 GMT

1. firewall to allow tcp/udp 123 on both
sides
2. modify ntp.conf, and step-tickers
3. restart ntpd
that's it