Sets the total expected votes in the OpenVMS Cluster to a value that you specify or, if no value is specified, sets the total votes to a value determined by the system.

Requires OPER (operator) privilege.

Format

SET CLUSTER/EXPECTED_VOTES [=value]

Parameter

value

Specifies the total number of expected votes in the cluster.

Description

The SET CLUSTER/EXPECTED_VOTES command enables you to adjust the total number of expected votes in the cluster. Set this value equal to the number of votes contributed by each node plus the number of votes contributed by the cluster quorum disk. The system will automatically calculate the value of the cluster quorum from the total number of expected votes in the cluster.

You can specify the expected total votes value as part of the SET CLUSTER/EXPECTED_VOTES command string. If you enter the command without specifying a value for expected votes, the system calculates the value for you, using the following formula:

EXPECTED_VOTES=(NODE1_VOTES+NODE2_VOTES+...)+QUORUM_DISK_VOTES

NODEn_VOTES is the value of the system parameter VOTES for each node in the cluster and QUORUM_DISK_VOTES is the value of the system parameter QDSKVOTES.

When you enter the SET CLUSTER/EXPECTED_VOTES command without specifying a value, the system assumes that all nodes that are expected to be in the cluster are currently members.

In general, you use the SET CLUSTER/EXPECTED_VOTES command only when a node is leaving the cluster for an extended period of time. Under normal circumstances, quorum is not reduced when a node leaves the cluster, because it is assumed that the node may be rebooted and rejoin the cluster. If a node is removed and is unable to rejoin the cluster within a reasonable period of time (for example, if a node crashes due to a hardware problem and cannot rejoin the cluster for several days), the quorum for the cluster can safely be reduced by lowering the total expected votes until that node rejoins.

The purpose of a cluster quorum is to eliminate any possibility of the cluster partitioning into separate clusters and simultaneously accessing the same resources (such as disks). If the sum of the votes for all members of the cluster is smaller than the cluster quorum, all nodes will block activity until new nodes join to increase the vote total. Lowering the quorum value (by reducing the value of the total expected votes) when one or more nodes leave the cluster for long periods of time reduces this possibility.

Note that no matter what value you specify for the SET CLUSTER/EXPECTED_VOTES command, you cannot increase quorum to a value that is greater than the number of the votes present, nor can you reduce quorum to a value that is half or fewer of the votes present.

When you enter the SET CLUSTER/EXPECTED_VOTES command, either with or without an expected votes value specified, the system responds with a message indicating the new value that was actually set. Note that you need to enter this command only on one node in the cluster, because the new value for total expected votes is propagated through the cluster. This new expected votes value should then be stored in the system parameter EXPECTED_VOTES on each node, so that it remains in effect after the nodes reboot.

When a node that was previously a member of the cluster is ready to rejoin, you should increase the system parameter EXPECTED_VOTES to its original value before bringing the node back to the cluster. Note that you do not need to use the SET CLUSTER/EXPECTED_VOTES command to increase the number of expected votes, because the expected votes value will be increased automatically when the node rejoins the cluster.

Examples

$ SET CLUSTER/EXPECTED_VOTES
      

The SET CLUSTER command in this example instructs the system to calculate the total expected votes value for you, because no value is specified as part of the command string. The system uses the NODEn_VOTES + QUORUM_DISK_VOTES formula.

$ SET CLUSTER/EXPECTED_VOTES=9
      

The SET CLUSTER command in this example sets the total expected votes to 9, which is the value specified in the command string.