3.11. Checking the Cluster Configuration

To ensure that the cluster software has been correctly configured, use the following tools located in the /usr/sbin directory:

The following section explains the cluster utilities in further detail.

3.11.1. Testing the Shared Partitions

The shared partitions must refer to the same physical device on all members. Invoke the /usr/sbin/shutil utility with the -v command to test the shared partitions and verify that they are accessible.

If the command succeeds, run the /usr/sbin/shutil -p /cluster/header command on all members to display a summary of the header data structure for the shared partitions. If the output is different on the members, the shared partitions do not point to the same devices on all members. Check to make sure that the raw devices exist and are correctly specified in the /etc/sysconfig/rawdevices file. See Section Configuring Shared Cluster Partitions for more information.

The following example shows that the shared partitions refer to the same physical device on cluster members clu1.example.com and clu2.example.com via the /usr/sbin/shutil -p /cluster/header command:

/cluster/header is 140 bytes long
SharedStateHeader {
        ss_magic = 0x39119fcd
        ss_timestamp = 0x000000003ecbc215 (14:14:45 May 21 2003)
        ss_updateHost = clu1.example.com

All fields in the output from the /usr/sbin/shutil -p /cluster/header command should be the same when run on all cluster members. If the output is not the same on all members, perform the following:

After performing these tasks, re-run the /usr/sbin/shutil utility with the -p option.

3.11.2. Testing the Power Switches

If either network-attached or serial-attached power switches are employed in the cluster hardware configuration, install the cluster software and invoke the clufence command to test the power switches. Invoke the command on each member to ensure that it can remotely power-cycle the other member. If testing is successful, then the cluster can be started.

The clufence command can accurately test a power switch only if the cluster software is not running. This is due to the fact that for serial attached switches, only one program at a time can access the serial port that connects a power switch to a member. When the clufence command is invoked, it checks the status of the cluster software. If the cluster software is running, the command exits with a message to stop the cluster software.

The clufence command line options are as follows:

When testing power switches, the first step is to ensure that each cluster member can successfully communicate with its attached power switch. The following output of the clufence command shows that the cluster member is able to communicate with its power switch:

[27734] info: STONITH: rps10 at /dev/ttyS0, port 0 controls clumember1.example.com
[27734] info: STONITH: rps10 at /dev/ttyS0, port 1 controls clumember2.example.com

In the event of an error in the clufence output, check the following:

After successfully verifying communication with the switch, attempt to power cycle the other cluster member. Prior to doing this, we recommend you verify that the other cluster member is not actively performing any important functions (such as serving cluster services to active clients). Running the command clufence -f clumember2.example.com displays the following output upon a successful shutdown and fencing operation (which means that the system does not receive power from the power switch until the system has been unfenced):

[7397] info: STONITH: rps10 at /dev/ttyS0, port 0 controls clumember1.example.com
[7397] info: STONITH: rps10 at /dev/ttyS0, port 1 controls clumember2.example.com
[7397] notice: STONITH: clumember2.example.com has been fenced!

3.11.3. Displaying the Cluster Software Version

Ensure that all members in the cluster are running the same version of the Red Hat Cluster Manager software.

To display the version of the Cluster Configuration Tool and the Cluster Status Tool, use either of the following methods: