6.2.5 Configuring the Cluster Stack

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6.2.5 Configuring the Cluster Stack

To configure the cluster stack:

Run the following command on each node of the cluster:

# service o2cb configure

The following table describes the values for which you are prompted.

Prompt	Description
`Load O2CB driver on boot (y/n)`	Whether the cluster stack driver should be loaded at boot time. The default response is `n`.
`Cluster stack backing O2CB`	The name of the cluster stack service. The default and usual response is `o2cb`.
`Cluster to start at boot (Enter "none" to clear)`	Enter the name of your cluster that you defined in the cluster configuration file, `/etc/ocfs2/cluster.conf`.
`Specify heartbeat dead threshold (>=7)`	The number of 2-second heartbeats that must elapse without response before a node is considered dead. To calculate the value to enter, divide the required threshold time period by 2 and add 1. For example, to set the threshold time period to 120 seconds, enter a value of 61. The default value is 31, which corresponds to a threshold time period of 60 seconds. Note If your system uses multipathed storage, the recommended value is 61 or greater.
`Specify network idle timeout in ms (>=5000)`	The time in milliseconds that must elapse before a network connection is considered dead. The default value is 30,000 milliseconds. Note For bonded network interfaces, the recommended value is 30,000 milliseconds or greater.
`Specify network keepalive delay in ms (>=1000)`	The maximum delay in milliseconds between sending keepalive packets to another node. The default and recommended value is 2,000 milliseconds.
`Specify network reconnect delay in ms (>=2000)`	The minimum delay in milliseconds between reconnection attempts if a network connection goes down. The default and recommended value is 2,000 milliseconds.

To verify the settings for the cluster stack, enter the service o2cb status command:

# service o2cb status
Driver for "configfs": Loaded
Filesystem "configfs": Mounted
Stack glue driver: Loaded
Stack plugin "o2cb": Loaded
Driver for "ocfs2_dlmfs": Loaded
Filesystem "ocfs2_dlmfs": Mounted
Checking O2CB cluster "mycluster": Online
  Heartbeat dead threshold: 61
  Network idle timeout: 30000
  Network keepalive delay: 2000
  Network reconnect delay: 2000
  Heartbeat mode: Local
Checking O2CB heartbeat: Active

In this example, the cluster is online and is using local heartbeat mode. If no volumes have been configured, the O2CB heartbeat is shown as Not active rather than Active.

The next example shows the command output for an online cluster that is using three global heartbeat devices:

# service o2cb status
Driver for "configfs": Loaded
Filesystem "configfs": Mounted
Stack glue driver: Loaded
Stack plugin "o2cb": Loaded
Driver for "ocfs2_dlmfs": Loaded
Filesystem "ocfs2_dlmfs": Mounted
Checking O2CB cluster "mycluster": Online
  Heartbeat dead threshold: 61
  Network idle timeout: 30000
  Network keepalive delay: 2000
  Network reconnect delay: 2000
  Heartbeat mode: Global
Checking O2CB heartbeat: Active
  7DA5015346C245E6A41AA85E2E7EA3CF /dev/sdd
  4F9FBB0D9B6341729F21A8891B9A05BD /dev/sdg
  B423C7EEE9FC426790FC411972C91CC3 /dev/sdj

Configure the o2cb and ocfs2 services so that they start at boot time after networking is enabled:
```
# chkconfig o2cb on
# chkconfig ocfs2 on
```
These settings allow the node to mount OCFS2 volumes automatically when the system starts.