Checking the Cluster Configuration

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

The following section explains the cluster utilities in further detail.

Testing the Quorum Partitions

The quorum partitions must refer to the same physical device on both cluster systems. Invoke the cludiskutil utility with the -t command to test the quorum partitions and verify that they are accessible.

If the command succeeds, run the cludiskutil -p command on both cluster systems to display a summary of the header data structure for the quorum partitions. If the output is different on the systems, the quorum partitions do not point to the same devices on both systems. Check to make sure that the raw devices exist and are correctly specified in the /etc/sysconfig/rawdevices file. See the Section called Configuring Quorum Partitions in Chapter 2 for more information.

The following example shows that the quorum partitions refer to the same physical device on two cluster systems (devel0 and devel1):

/sbin/cludiskutil -p
----- Shared State Header ------
Magic# = 0x39119fcd
Version = 1
Updated on Thu Sep 14 05:43:18 2000
Updated by node 0
--------------------------------


/sbin/cludiskutil -p
----- Shared State Header ------
Magic# = 0x39119fcd
Version = 1
Updated on Thu Sep 14 05:43:18 2000
Updated by node 0
--------------------------------

The Magic# and Version fields will be the same for all cluster configurations. The last two lines of output indicate the date that the quorum partitions were initialized with cludiskutil -I, and the numeric identifier for the cluster system that invoked the initialization command.

If the output of the cludiskutil utility with the -p option is not the same on both cluster systems, perform the following:

After performing these tasks, re-run the cludiskutil utility with the -p option.

Testing the Power Switches

If either network- or serial-attached power switches are employed in the cluster hardware configuration, install the cluster software and invoke the clustonith command to test the power switches. Invoke the command on each cluster system to ensure that it can remotely power-cycle the other cluster system. If testing is successful, then the cluster can be started. If using watchdog timers or the switch type "None", then this test can be omitted.

The clustonith 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 cluster system. When the clustonith 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 format of the clustonith command is as follows:

clustonith [-sSlLvr] [-t devicetype] [-F options-file] \
	  [-p stonith-parameters] 
Options:
-s              Silent mode, supresses error and log messages
-S              Display switch status
-l              List the hosts a switch can access
-L              List the set of supported switch types
-r hostname     Power cycle the specified host
-v              Increases verbose debugging level

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

  clustonith -S
WTI Network Power Switch device OK. 
An example output of the clustonith command when it is unable 
to communicate with its power switch appears below: 
  clustonith -S 
Unable to determine power switch type. 
Unable to determine default power switch type. 

The above error could be indicative of the following types of problems:

After successfully verifying communication with the switch, attempt to power cycle the other cluster member. Prior to doing this, it would is recommended to verify that the other cluster member is not actively performing any important functions (such as serving cluster services to active clients). The following command depicts a successful power cycle operation:

clustonith -r clu3
Successfully power cycled host clu3. 

Displaying the Cluster Software Version

Invoke the rpm -qa clumanager command to display the revision of the installed cluster RPM. Ensure that both cluster systems are running the same version.