Again about Time syncronization

[Patrick Chim]

Hi all,

Here are some concern with the time syncronization using xntpd

1. Is it possible to run MC/Service Guard and xntpd simultaneously ?
2. If so, what I have to concern ? If not, is there any alternative method ?
3. If the time of the standby server is slower than that of the production server, what will happen to the cluster if xntpd really want to syncronize the time (will it affect the timeout period of the heartbeat or anything else) ?

Thank you for your kind attention !

Patrick

[melvyn burnard · Accepted solution]

To answer your questions:
1. Yes they can run together and in fact it is recommended to use xntp within a cluster.

2. not applicable :-}

3. xntp will slew in the time slowly and will not cause any problems in that respect. What you should do is to get the system times syncrhonised fairly closely before starting the cluster. What you should NEVER do is change the date/time drastically while the node is running in a cluster as you will get a TOC.

[Shannon Petry]

I can not see why MC Service Guard and xntpd would have problems living together.
However, you do not have to use xntp, and ntpdate. You can use rdate to accomplish the same thing for most respects.
you may have to do a bit of your own scripting, but both grab remote dates from remote servers, and allow manipulation of local clocks.

Regards,
Shannon

[Bill Hassell]

In MC/SG, I would not recommend any other method to sync the time except NTP. NTP will maintain the time to less 128 ms accuracy. Syncing the time is very important to databases and making multi-second (or worse, multi-minute) changes in time can create some big problems. Tell all sysadmins to NEVER set the time of day with database programs running.