4.12.1 How to Reserve Shared Devices (SSVM and CVM)

When new shared disk groups are imported while one or more nodes are not in the cluster, the cluster must be informed that an extra set of devices need failure fencing. This is accomplished by running the scadmin resdisk command from a node that can access the new disk group(s).

# scadmin resdisks

This command reserves all the devices connected to a node if no other node (that has connectivity to the same set of devices) is in the cluster membership. That is, reservations are affected only if one and only one node, out of all possible nodes that have direct physical connectivity to the devices, is in the cluster membership. If this condition is false, the scadmin resdisks command has no effect. The command also fails if a cluster reconfiguration is in progress. Reservations on shared devices are automatically released when this one node is shut down, or when other nodes, with direct connectivity to the shared devices, join the cluster membership.

It is unnecessary to run the scadmin resdisks command if shared disk groups are imported while all nodes are in the cluster. Reservations and failure fencing are not relevant if full cluster membership is present.

However, if a shared disk group is deported, the reservations on the shared devices in the deported disk group are not released. These reservations are not released until either the node that does the reservations is shut down, or the other node, with which it shares devices, joins the cluster.

To enable the set of disks belonging to the deported disk group to be used immediately, enter the following two commands in succession on all cluster nodes, after deporting the shared disk group:

# scadmin reldisks
# scadmin resdisks

The first command releases reservations on all shared devices. The second command effectively redoes the reservations based on the currently imported set of disk groups, and automatically excludes the set of disks associated with deported disk groups.