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.
Note - 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 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 How to Set the Desired Number of Secondaries (VERITAS Volume Manager).
Become superuser on any node of the cluster.
Enter the scsetup utility.
# scsetup
The Main Menu is displayed.
To work with VxVM disk device groups, type 4 (Device groups and volumes).
The Device Groups Menu is displayed.
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.
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 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.
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
Note - If you change any configuration information for a VxVM disk group or volume that is registered with the cluster, you must reregister 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.
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 |
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 How to Assign a New Minor Number to a Disk Device Group (VERITAS Volume Manager).
How to Register Disk Group Configuration Changes (VERITAS Volume Manager)
When you change any configuration information for a VxVM disk group or volume, you need to register the configuration changes for the Sun Cluster disk device group. Registration ensures that the global namespace is in the correct state.
Become superuser on any node in the cluster.
Run the scsetup(1M) utility.
# scsetup
The Main Menu is displayed.
To work with VxVM disk device groups, type 4 (Device groups and volumes).
The Device Groups Menu is displayed.
To register configuration changes, type 2 (Synchronize volume information for a VxVM device group).
Follow the instructions and enter the VxVM disk group that has changed configuration.
Example--Registering VERITAS Volume Manager Disk Group Configuration Changes
The following example shows the scconf command generated by scsetup when registering a changed VxVM disk device group (dg1). This example assumes that the VxVM disk group and volume were created previously.
# scsetup scconf -c -D name=dg1,sync |
How to Set the Desired Number of Secondaries (VERITAS Volume Manager)
The numsecondaries property specifies the number of nodes within a device group that can master the group if the primary node fails. The default number of secondaries for device services is one. The value can be set to any integer between one and the number of operational non-primary provider nodes in the device group.
This setting is an important factor in balancing cluster performance and availability. For example, increasing the desired number of secondaries increases the device group's opportunity to survive multiple failures that occur simultaneously within a cluster. Increasing the number of secondaries also decreases performance regularly during normal operation. A smaller number of secondaries typically results in better performance, but reduces availability. However, a larger number of secondaries does not always result in greater availability of the file system or device group in question. Refer to "Key Concepts - Administration and Application Development" in Sun Cluster 3.1 Concepts Guide for more information.
Become superuser on any node of the cluster.
Run the scsetup(1M) utility.
# scsetup
The Main Menu is displayed.
To work with VxVM disk device groups, type 4 (Device groups and volumes).
The Device Groups Menu is displayed.
To change key properties of a device group, type 6 (Change key properties of a device group).
The Change Key Properties Menu is displayed.
To change the desired number of secondaries, type 2 (Change the numsecondaries property).
Follow the instructions and type the desired number of secondaries to be configured for the disk device group. After an appropriate value has been typed, the corresponding scconf command is executed. Following, a log is printed, and the user is returned to the previous menu.
Validate the device group configuration by using the scconf -p command.
# scconf -p | grep Device Device group name: dg-schost-1 Device group type: VxVM Device group failback enabled: yes Device group node list: phys-schost-1,phys-scot-2, phys-schst-3 Device group ordered node list: yes Device group desired number of secondaries: 1 Device group diskset name: dg-schost-1
Note - If you change any configuration information for a VxVM disk group or volume that is registered with the cluster, you must reregister the disk device group by using scsetup. 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.
Verify the primary node and status for the disk device group.
# scstat -D