system time is faster than real time

[Rambo_1]

I have a superdome. I found the system time was faster than the real time after I rebooted it yesterday. for example.If the system time is m 8:00 and the real time will already be am9:00 .I used date command to modify the time this moring ,but I found the time still faster than the real time at afternoon!!
Can anyone tell me what is the cause ?

Thanks
Rambo

[V. Nyga]

Hi,

seems like your superdome is configured for a 50 Hz electric power supply - and you have 60 Hz?
So the faster oscillation let your clock run faster ...

Volkmar

[Bill Hassell · Accepted solution]

The system's power supply has no effect on the clock. Virtually all recent servers have auto-ranging power supplies and handle 50 or 60 Hz without adjustment.

It is normal for the clock to drift a few seconds per day, even a minute or so. That's why *ALL* data centers should be running NTP with a central time server.

Now if you are seeing an hour difference, DO NOT change the clock. Instead, look at the HP-UX system time with date -u. That is UTC (GMT or Zulu) time which you can verify with:

http://tycho.usno.navy.mil/cgi-bin/timer.pl

You set the correct time for HP-UX using date -u because there are no timezone calculations for UTC time. Once that is correct, when you type the date command, look at the timezone tag at the end. HP-UX calculates the time based on the variable $TZ and this can be set anywhere (/etc/profile, .profile, manually, etc). So don't change the time if date -u is correct for UTC time. Instead, change your TZ variable. The default value for everyone is set in the file: /etc/TIMEZONE

[Rambo_1]

so thanks for the reply .I will use the NTP to synchronize the time between both of severs.

Thanks & B.R
Rambo

[skt_skt]

Client side

# The NTP peer group...
#
server server1 version 3
server server2 version 3
server server3 version 3

#
# Allow server to sync to its own clock in case of network outage.
# Clock is configured as a stratum-9 clock

server 127.127.1.0
fudge 127.127.1.0 stratum 10 # show poor quality
driftfile /etc/ntp.drift


server(server1) side

peer server2
peer server3

#
# Allow server to sync to its own clock in case of network outage.
# Clock is configured as a stratum-9 clock

server 127.127.1.1
#fudge 127.127.1.1 stratum 10 # show poor quality
fudge 127.127.1.1 stratum 5
driftfile /etc/ntp.drift

that may help..

[Rambo_1]

"driftfile /etc/ntp.drift"

what is the meaning ?

Thanks

[John Payne_2]

The drift file will show you the "frequency offset", so says the man page...

Basically, this helps xntpd understand how often it needs to check the time. (If your clock is off a little, it will help xntpd check more often to keep you closer to your clock.

Hope it helps

John