Managing HP Serviceguard A.12.00.00 for Linux, June 2014

8 Simulating a Serviceguard Cluster
Cluster simulation allows administrators to simulate different kinds of failures, such as node, network,
and workload failures (that is, Serviceguard packages). Cluster simulation is capable of simulating
node and network interface failures. Cluster simulation evaluates and analyzes what happens to
the package due to simulated failures, whether the packages will failover and start on a specified
node. The cluster states reported by the simulated cluster exactly matches with the real Serviceguard
cluster. This helps in analyzing high availability design for various failure scenarios.
Cluster simulation also enables the administrators to do the following:
• Run failure simulations on Serviceguard clusters.
• Import the state of the Serviceguard cluster in production environment and run the failure
simulation.
• Import the entire state of a deployed Serviceguard cluster into simulated environment for future
availability analysis.
• Repeat a pre-defined set of all possible failures in a cluster and check for points of failure.
Advantages
• The commands in the cluster simulation are almost similar to the Serviceguard cluster commands.
• You can run cluster simulation on production clusters since it does not interfere with the deployed
clusters.
• There is no need for the actual hardware to simulate a cluster. You can simulate up to 32
nodes in the cluster using a single node.
• You can also have multiple simulation sessions or clusters running on the same node
simultaneously.
Modes of Simulation
The simulation commands are supported with two modes, namely:
• Simulation prompt mode — In this mode, you can set the cluster or session using setcluster
command on which all further commands can be run without having to specify its name
explicitly with --session option. For example, #cmsimulatecl clsim> setcluster
test_cluster clsim:test_cluster>
• Simulation command-line interface mode — In this mode, you can run the Serviceguard
simulation command from the shell. For example, #cmsimulatecl cmapplyconf -C
test_cluster.ascii
Not Supported
The following Serviceguard features are not supported on the simulated cluster:
• The cmquerycl, cmgetconf, cmcheckconf, and cmcheckdisk commands.
• The -t preview option with any Serviceguard command.
• LAD, Generic Resource, Load Balancing, serviceguard-xdc, Cluster Analytics, VxFS, and Online
and offline reconfiguration of cluster and package.
• Failure scenarios of storage.
• The cmrunpkg -m and cmrunpkg -e option in maintenance mode.
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