NTP configuration on HP 11.2

[Mark2010_1]

Hello,

We have few servers rp3440/rp4410/rp4440 running HP UX 11.2 that we want to synchronize with an NTP server xntpd3.4 (Sun).

My questions are:

- Does HPUX 11.2 support NTP V4. If not what are the patches to be installed and other requirements.

- Does HPUX 11.2 support NTP V3 and what are the patches to be installed and other requirements.

- What is the procedure to set rp servers as client of the master. and how to check sychronization is ok.

Thanks in advance

[James R. Ferguson · Accepted solution]

Hi:

HP-UX uses NTP version 3. Version 4 is a develpment version that has not yet reached formal acceptance as a standard. NTP version 3 is available as part of a standard installation, simply requiring your configuration. For configuration details, see:

http://www.docs.hp.com/en/B2355-91060/ch04.html

http://www.ntp.org/

Be sure to choose at least three (3) external time sources. The world-wide pool is an excellent source:

http://www.pool.ntp.org/

If you choose, SAM can be used to perform the very simple configuation of '/etc/ntp.conf' and 'etc/rc.config.d/netdaemons'.

If you wish to download, install and compile NTP version 4, you can from here:

http://www.ntp.org/downloads.html

Regards!

...JRF...

[Matti_Kurkela]

HP-UX 11.23 certainly supports NTP V3, as even the old HP-UX 11.00 supported that.

"man xntpd" does not mention NTP V4 at all, so I'll have to conclude that V4 is not supported. A search on ITRC patch database does not turn up any patches related to enabling NTP V4 support.

Looks like NTP V3 is your only choice.

Before enabling NTP synchronization, use the "ntpdate" command to make the rp server's clock roughly in sync with the NTP server.

There are two ways to configure rp servers to become NTP clients. One way is to edit /etc/ntp.conf and /etc/rc.config.d/netdaemons as appropriate, and then start the xntpd daemon with "/sbin/init.d/xntpd start".

The other, much simpler way is to use SAM.

The NTP settings are in the "Time" category of SAM. Go to "NTP network time sources", select "Add remote server or peer..." from the Actions menu, then fill the dialog with the necessary information (NTP server hostname or IP address, NTP version and the NTP authentication key if your server is configured to use NTP authentication).
After you've completed this dialog, select "Start NTP" from the Actions menu. You're done.

To check the synchronization, use "ntpq -p" command after the NTP daemon has been running for a while.

There should be an asterisk at the left-most column on one of the output lines: this indicates that the daemon has successfully synchronized with that NTP server.

The "reach" column has a number in octal, in which each bit indicates a successful reception of a time message. The normal value in long-term use is 377: it means the last 8 time queries have been successful. When you've just started NTP, you should see this value gradually climb to 377. For example, the value 307 would be 11000111 in binary: it would indicate a temporary communication failure (the connection was working, then a failure caused 3 queries to fail, then the latest 3 queries were successful again).

The "delay" column indicates the round-trip time in the communication with the NTP server, measured in milliseconds. If your NTP server is not located very far from you in the network, this should be fairly small.

The "offset" is the calculated difference between the local clock and the NTP server's clock in milliseconds: the NTP daemon will adjust the clock to make this as small as possible. If the offset is larger than 128 milliseconds, NTP considers to be "out of sync".

The "disp" is dispersion, in milliseconds: if this is about 100 or higher, NTP will have difficulties in achieving sync and keeping the clocks synchronized. High dispersion might mean that the network between this server and your NTP master server is congested, or that either the local server's or the NTP master's clock is not stable.

MK

[TY 007]

Hello Mark,

>> NTP V3 and what are the patches to be installed and other requirements

PHNE_31739 NTP timeservices upgrade plus utilities
PHCO_34974 cumulative SAM patch
PHCO_36454 auto_parms/set_parms/dhcpdb2conf

Thanks

[Mark2010_1]

Hi again,

But if we decide to change the time on a given server should we stop SG and other appalications or not ?

Cause there is many applications using file with time stamping and for sure these applications are gonna to be lost.

BR

[James R. Ferguson]

Hi (again):

> But if we decide to change the time on a given server should we stop SG and other appalications or not ?

When you initially setup NTP, is is necessary to establish a server's time relatively close to the correct value. Manually moving time backwards when databases or time-sensitve appplications are running is disruptive and may compromise database recovery should that be necessary. Moving time forward is usually benign.

NTP will fail to start if the time difference between its source and the local, server time exceeds 1000 seconds. Large deltas will also take a long adjustment period since NTP makes small incremental changes in the local server time to smooth transitions.

All said, the easiest way to initially establish your time synchronization if your server's time is more than a couple of minutes different from true time, is to reboot. First, configure '/etc/rc.config.d/netdaemons' to set the NTPDATE_SERVER variable equal to an NTP time server that is reachable. During startup (reboot), this will run '/usr/sbin/ntpdate' immediately before the NTP daemon is started, and bring the system clock close to the correct time. Thereafter, the NTP daemon keeps everything synchronized.

Regards!

...JRF...