SPARC: How to Register a Disk Group as a Disk Device Group (VERITAS Volume Manager)

This procedure uses the scsetup(1M) utility to register the associated VxVM disk group as a Sun Cluster disk device group.

After a disk device group has been registered with the cluster, never import or deport a VxVM disk group by using VxVM commands. If you make a change to the VxVM disk group or volume, use the procedure SPARC: How to Register Disk Group Configuration Changes (VERITAS Volume Manager) to register the disk device group configuration changes. This procedure ensures that the global namespace is in the correct state.

The prerequisites to register a VxVM disk device group are:

• Superuser privilege on a node in the cluster.

• The name of the VxVM disk group to be registered as a disk device group.

• A preferred order of nodes to master the disk device group.

• A desired number of secondary nodes for the disk device group.

When you define the preference order, you also specify whether you want the disk device group to be switched back to the most preferred node in the event that the most preferred node goes down and later returns to the cluster.

See scconf(1M) for more information on node preference and failback options.

Non-primary cluster nodes (spares) transition to secondary according to the node preference order. The default number of secondaries for a device group is normally set to one. This default setting minimizes performance degradation caused by primary checkpointing of multiple secondary nodes during normal operation. For example, in a four node cluster, the default behavior configures one primary, one secondary, and two spare nodes. See also SPARC: How to Set the Desired Number of Secondaries (VERITAS Volume Manager).

1. Become superuser on any node of the cluster.

2. Enter the scsetup utility.

   # scsetup

   The Main Menu is displayed.

3. To work with VxVM disk device groups, type 4 (Device groups and volumes).

   The Device Groups Menu is displayed.

4. To register a VxVM disk device group, type 1 (Register a VxVM disk group as a device group).

   Follow the instructions and enter the name of the VxVM disk group to be registered as a Sun Cluster disk device group.

   If you use VxVM to set up shared disk groups for Oracle Parallel Server/Real Application Clusters, you do not register the shared disk groups with the cluster framework. Use the cluster functionality of VxVM as described in the VERITAS Volume Manager Administrator's Reference Guide.

5. If you encounter the following error while attempting to register the disk device group, reminor the disk device group.

   scconf: Failed to add device group - in use

   To reminor the disk device group, use the procedure SPARC: How to Assign a New Minor Number to a Disk Device Group (VERITAS Volume Manager). This procedure enables you to assign a new minor number that does not conflict with a minor number used by an existing disk device group.

6. Verify that the disk device group is registered and online.

   If the disk device group is properly registered, information for the new disk device group displays when using the following command.

   # scstat -D

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   Note –

   If you change any configuration information for a VxVM disk group or volume that is registered with the cluster, you must synchronize the disk device group by using scsetup(1M). Such configuration changes include adding or removing volumes, as well as changing the group, owner, or permissions of existing volumes. Reregistration after configuration changes ensures that the global namespace is in the correct state. See How to Update the Global Device Namespace.

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SPARC: Example—Registering a VERITAS Volume Manager Disk Device Group

The following example shows the scconf command generated by scsetup when registering a VxVM disk device group (dg1), and the verification step. This example assumes that the VxVM disk group and volume were created previously.

# scsetup

scconf -a -D type=vxvm,name=dg1,nodelist=phys-schost-1:phys-schost-2

# scstat -D
-- Device Group Servers --
                         Device Group      Primary           Secondary
                         ------------      -------           ---------
Device group servers:    dg1              phys-schost-1      phys-schost-2
 
-- Device Group Status --
                              Device Group        Status              
                              ------------        ------              
  Device group status:        dg1                 Online

SPARC: Where to Go From Here

To create a cluster file system on the VxVM disk device group, see How to Add a Cluster File System.

If there are problems with the minor number, see SPARC: How to Assign a New Minor Number to a Disk Device Group (VERITAS Volume Manager).