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 Configuring OPS Clusters with MC/LockManager: > Chapter 5 Building an OPS Cluster Configuration

Distributing the Binary Configuration File
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After specifying all cluster parameters, you use SAM or HP-UX commands to apply the configuration. This action distributes the binary configuration file to all the nodes in the cluster. We recommend doing this separately before you configure packages (described in the next chapter). In this way, you can verify the cluster lock, heartbeat networks, and other cluster-level operations by using the cmviewcl command on the running cluster. Before distributing the configuration, ensure that your security files permit copying among the cluster nodes. See "Preparing Your Systems" at the beginning of this chapter.

Distributing the Configuration File with SAM

When you have finished entering parameters in the Cluster Configuration subarea in SAM, you are asked to verify the copying of the files to all the nodes in the cluster. When you respond OK to the verification prompt, MC/LockManager copies the binary configuration file and the ASCII configuration file to all the nodes in the cluster.

Distributing the Configuration File with HP-UX Commands

Use the following steps to generate the binary configuration file and distribute the configuration to all nodes in the cluster:

  • Activate the cluster lock volume group so that the lock disk can be initialized:

    # vgchange -a y /dev/vglock

  • Generate the binary configuration file and distribute it across the nodes.

    # cmapplyconf -v -C /etc/cmcluster/cmclconf.ascii

  • Deactivate the cluster lock volume group.

    # vgchange -a n /dev/vglock

The cmapplyconf command creates a binary version of the cluster configuration file and distributes it to all nodes in the cluster. This action ensures that the contents of the file are consistent across all nodes. Note that the cmapplyconf command does not distribute the ASCII configuration file.

CAUTION: The cluster lock volume group must be activated only on the node from which you issue the cmapplyconf command, so that the lock disk can be initialized. If you attempt to configure a cluster either using SAM or by issuing the cmapplyconf command on one node while the lock volume group is active on another, different node, the cluster lock will be left in an unknown state. Therefore, you must ensure that when you configure the cluster, the cluster lock volume group is active only on the configuration node and deactivated on all other nodes.

Be sure to deactivate the cluster lock volume group on the configuration node after cmapplyconf is executed.

Storing Volume Group and Cluster Lock Configuration Data

After creating the cluster configuration with SAM or with HP-UX commands, make a backup copy of the volume group configuration data by using the vgcfgbackup command for each cluster aware volume group you have created. If a disk in a volume group must be replaced, you can then restore the disk's metadata by using the vgcfgrestore command. The procedure is described under "Replacing Disks" in the "Troubleshooting" chapter.

Be sure to use vgcfgbackup for all cluster and OPS volume groups, including the cluster lock volume group, when you first create the cluster. Use the command again for each new cluster aware volume group that you add with SAM or with HP-UX commands.

NOTE: The lock disk is normally configured with redundant copies either through mirroring or RAID. If the cluster lock disk ever needs to be replaced while the cluster is running, you must use the vgcfgrestore command to restore lock information to the replacement disk. Failure to do this might result in a failure of the entire cluster if all redundant copies of the lock disk have failed and if replacement mechanisms or LUNs have not had the lock configuration restored.

Checking Cluster Operation

MC/LockManager also provides several commands for manual control of the cluster:

  • cmrunnode is used to start a node.

  • cmhaltnode is used to manually stop a running node. (This command is also used by shutdown(1m).)

  • cmruncl is used to manually start a stopped cluster.

  • cmhaltcl is used to manually stop a cluster.

You can use these commands to test cluster operation, as in the following:

  1. If the cluster is not already online, run the cluster, as follows:

    # cmruncl -f -v

  2. When the cluster has started, use the following command to ensure that cluster components are operating correctly:

    # cmviewcl -v

    Make sure that all nodes and networks are functioning as expected. For information about using cmviewcl, refer to the chapter on "Cluster and Package Maintenance."

  3. Use the following sequence of commands to verify that nodes leave and enter the cluster as expected:

    • On a cluster node, issue the cmhaltnode command.

    • Use the cmviewcl command to verify that the node has left the cluster.

    • Issue the cmrunnode command.

    • Use the cmviewcl command again to verify that the node has returned to operation.

  4. Use the following command to bring down the cluster:

    # cmhaltcl -v -f

Additional cluster testing is described in the "Troubleshooting" chapter. Refer to Appendix A for a complete list of MC/LockManager commands



Verifying the Cluster Configuration
  		 


Preventing Automatic Activation of Volume Groups  
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