Managing the cluster time (cluster administrators only)

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Cluster : Configuration > System Tools > DateTime : Managing the cluster time (cluster administrators only)

Managing the cluster time (cluster administrators only)

Problems can occur when the cluster time is inaccurate. You can manually set the time zone, date, and time on the cluster. However, it is best to keep your cluster time synchronized automatically by using the Network Time Protocol (NTP) servers.

Data ONTAP enables you to manage the cluster time in the following ways:

•	Configuring the NTP servers

On a cluster running Data ONTAP 8.2 and later releases, NTP is always enabled on the cluster. To disable NTP (not recommended), you must contact technical support.

Although NTP is always enabled, for the cluster to synchronize with an external time source, you must configure the NTP servers. The system services ntp server commands enable you to manage the NTP servers in the following ways:

•	Associating a node with an NTP server

You can get a list of public NTP time servers from the NTP Public Services page.

•	Specifying the preferred NTP server and version for a node

Data ONTAP 8.0 and 8.0.1 use NTP v4 by default. To address situations where certain time servers support only NTP v3, starting with Data ONTAP 8.0.2, the NTP version to be used for communicating with a newly configured NTP server defaults to v3 instead of v4. The NTP Daemon continues to use the highest supported version (v4 in this case) to communicate with the time servers that were configured prior to Data ONTAP 8.0.2.

•	Displaying information about NTP servers that are associated with a node or the cluster

•	Dissociating a node from an NTP server

For more information about the system services ntp server commands, see the man pages.

•	Manually setting the cluster time

Data ONTAP enables you to manually manage the cluster time. The time you set takes effect across all nodes in the cluster. This capability is helpful for the following purposes:

•	Ensuring the intra-cluster time consistency

If no external time server is used, setting the cluster time manually ensures a time setting that is consistent across all nodes in the cluster.

•	Manually correcting erroneous cluster time

Even if an external time server is used, it is possible for the times on the nodes to become significantly incorrect (for example, a node's time has become incorrect after a reboot). In that case, you can manually specify an approximate time for the cluster until NTP can synchronize with an external time server.

The cluster date commands enable you to manually manage the cluster time in the following ways:

•	Setting or modifying the time zone, date, and time on the cluster

•	Displaying the current time zone, date, and time settings of the cluster

For more information about the cluster date commands, see the man pages.

Note: Job schedules do not adjust to manual cluster date and time changes. These jobs are scheduled to run based on the current cluster time when the job was created or when the job most recently ran. Therefore, if you manually change the cluster date or time, you must use the job show and job history show commands to verify that all scheduled jobs are queued and completed according to your requirements.

Next Topic

Setting the time for a cluster

You can use the Edit DateTime dialog box to manually set or modify the time zone for your cluster. You can also add time servers to the cluster.

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