Objects Administration Overview (VxVM)

Objects under the control of a volume manager are created and administered using either command-line utilities or the Visual Administrator graphical user interface.

Read the information in this chapter before using the VxVM documentation to administer objects under the control of a volume manager in a Sun Cluster configuration. The procedures presented here are one method for performing the following tasks. Use the method that works best for your particular configuration.

These objects generally have the following relationship:

• Disks are placed under volume manger control and are grouped into disk groups.

• One or more subdisks (each representing a specific portion of a disk) are combined to form plexes, or mirrors.

• A volume is composed of one or more plexes.

The default disk group is rootdg (the root disk group). You can create additional disk groups as necessary. The primary administration tasks that you perform on disk groups involve adding and removing disks.

Before using a disk that you have placed in a disk group, you must set up disks and subdisks (under volume manager control) to build plexes, or mirrors, using the physical disk's slices. A plex can be a concatenation or stripe.

With VxVM, applications access volumes (created on volume manager disks) rather than slices.

The following sections describe the VxVM command-line programs to use when performing a task. Optionally, you can use the graphical user interface for all the tasks unless directed otherwise.

On nodes running Sun Cluster HA data services, never manually run the vxdg import or deport options on a disk group that is under the control of Sun Cluster, unless the logical host for that disk group is in maintenance mode. Before manually importing or deporting a disk group, you must either stop Sun Cluster on all nodes that can master that disk group (by running scadmin stopnode on all such nodes), or use the haswitch -m command to switch any corresponding logical host into maintenance mode. When you are ready to return control of the disk group to Sun Cluster, the safest course is to deport the disk group before running scadmin startnode or before using haswitch(1M) to place the logical host back under the control of Sun Cluster.