OpenVMS Cluster Systems - OpenVMS Systems - HP
OpenVMS Cluster Systems - OpenVMS Systems - HP
OpenVMS Cluster Systems - OpenVMS Systems - HP
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Maintaining an <strong>OpenVMS</strong> <strong>Cluster</strong> System<br />
10.12 Restoring <strong>Cluster</strong> Quorum<br />
Table 10–6 Reducing the Value of <strong>Cluster</strong> Quorum<br />
Technique Description<br />
Use the DCL<br />
command SET<br />
CLUSTER/EXPECTED_<br />
VOTES to adjust the<br />
cluster quorum to a<br />
value you specify.<br />
Use the IPC Q command<br />
to recalculate the<br />
quorum.<br />
Select one of the clusterrelated<br />
shutdown<br />
options.<br />
If you do not specify a value, the operating system calculates an appropriate value for you.<br />
You need to enter the command on only one computer to propagate the new value throughout<br />
the cluster. When you enter the command, the operating system reports the new value.<br />
Suggestion: Normally, you use the SET CLUSTER/EXPECTED_VOTES command only<br />
after a computer has left the cluster for an extended period. (For more information about<br />
this command, see the <strong>OpenVMS</strong> DCL Dictionary.)<br />
Example: For example, if you want to change expected votes to set the cluster quorum to 2,<br />
enter the following command:<br />
$ SET CLUSTER/EXPECTED_VOTES=3<br />
10.13 <strong>Cluster</strong> Performance<br />
The resulting value for quorum is (3 + 2)/2 = 2.<br />
Note: No matter what value you specify for the SET CLUSTER/EXPECTED_VOTES<br />
command, you cannot increase quorum to a value that is greater than the number of the<br />
votes present, nor can you reduce quorum to a value that is half or fewer of the votes present.<br />
When a computer that previously was a cluster member is ready to rejoin, you must reset<br />
the EXPECTED_VOTES system parameter to its original value in MODPARAMS.DAT on<br />
all computers and then reconfigure the cluster according to the instructions in Section 8.6.<br />
You do not need to use the SET CLUSTER/EXPECTED_VOTES command to increase cluster<br />
quorum, because the quorum value is increased automatically when the computer rejoins the<br />
cluster.<br />
Refer to the <strong>OpenVMS</strong> System Manager’s Manual, Volume 1: Essentials for a description of<br />
the Q command.<br />
Refer to Section 10.7 for a description of the shutdown options.<br />
Sometimes performance issues involve monitoring and tuning applications and<br />
the system as a whole. Tuning involves collecting and reporting on system and<br />
network processes to improve performance. A number of tools can help you collect<br />
information about an active system and its applications.<br />
10.13.1 Using the SHOW Commands<br />
The following table briefly describes the SHOW commands available with the<br />
<strong>OpenVMS</strong> operating system. Use the SHOW DEVICE commands and qualifiers<br />
shown in the table.<br />
Command Purpose<br />
SHOW DEVICE/FULL Shows the complete status of a device, including:<br />
10–20 Maintaining an <strong>OpenVMS</strong> <strong>Cluster</strong> System<br />
• Whether the disk is available to the cluster<br />
• Whether the disk is MSCP served or dual ported<br />
• The name and type (VAX or HSC) of the primary and secondary hosts<br />
• Whether the disk is mounted on the system where you enter the<br />
command<br />
• The systems in the cluster on which the disk is mounted
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