Changeing the time in Cluster

[Jayasuntar]

Hi all,

We have 3* 2node clusters. One of the server in the cluster is configured as time server. All other servers are peer server to this node.

Now we want to change the time, since all the systems are runing 10 minutes behind the correct time. Can anybody tell , what is the procedure like, whether we need to bring down the cluster?, whether we need to change the time in all the serevr or only to the time server?. We have oracle DB running, whether we need to bring down the DB?..

Quick correct responses will get full mark..

Regards

Jay

[Devender Khatana · Accepted solution]

Hi,

Atleast the database package should be stopped while adjusting time backwards. Cluster has nothing to do with the time change but applications like database have problem in adjusting time online.

Changing time in only time server will be enough, other clients will automatically sync time with the time server but will take some time (15-20 Minutes) depending upon the difference in old and new times. For 10 minutes it should be not more than 20 minutes.

Also wait for all clients to sync with time server before starting applications.

HTH,
Devender

[Steven E. Protter]

Shalom Jay,

If the time rolls back on an active Oracle instance, the database will crash.

It is best to stop the cluster, adjust the time and bring it back up.

Note that rolling the time forward would not cause disrution.

Also: If you use ntp to adjust the time, ie they are not very far off, then the adjustment will be very slow, the clock will run a little faster or slower for a few hours until everything is in synch.

Practically speaking, I've gotten away with doing forward time adjustments in clustes with no negative impact. The smart way is to use ntp or bring the clsuter down.

SEP

[Jayasuntar]

Dear SEP & Devender,

I want to change the time 10 mins forward only, ( my server is 10 mins behind the normal time).

We have NTP configured in all the server. But all the servers are peer node to one of the node in cluster. Example, we have node1, 2, 3, 4, 5 and 6 servers. All are configured with NTP, and node node1 is cofigure to follow the local clock. All other servers are configured as peer node for node1.

Now please tell me which is the better way to change the time?..

Regards

Jay

[Steven E. Protter]

Shalom again,

Total saftey: Stop the cluster adjust the time on the node that is the ntp server. I'd suggest connecting cluster members ntp setup if possible to a node outside the cluster.

Common sense: A forward adjustment of the time on the node that is a server within the cluster will not disrupt the cluster.

Common sense II: For accuracy, there has to be a direct or indirect connection of your ntp setup to a good time source outside your network, or one of those new satellite devices that gets time from the US governments nuclear clocks.

SEP

[Devender Khatana]

Hi,

Stop the packages running and change the time on time server. It will sync by itself on the relevant nodes in 15-20 minutes. For making the sync slightly faster you can adjust the time on nodes as well and then restart the xntpd daemon by

#/sbin/init.d/xntpd stop

#/sbin/init.d/xntpd start

HTH,
Devender

[Jayasuntar]

Thanks a lot SEP, and Devender..

Regards

Jay