Volumes

A volume is a virtual disk device that appears to applications, databases, and file systems like a physical disk device, but does not have the physical limitations of a physical disk device. A volume consists of one or more plexes, each holding a copy of the selected data in the volume. Due to its virtual nature, a volume is not restricted to a particular disk or a specific area of a disk. The configuration of a volume can be changed by using VxVM user interfaces. Configuration changes can be accomplished without causing disruption to applications or file systems that are using the volume. For example, a volume can be mirrored on separate disks or moved to use different disk storage.

VxVM uses the default naming conventions of vol## for volumes and vol##-## for plexes in a volume. For ease of administration, you can choose to select more meaningful names for the volumes that you create.

A volume may be created under the following constraints:

Figure: Example of a volume with one plex shows a volume vol01 with a single plex.

Figure: Example of a volume with one plex

Example of a volume with one plex

The volume vol01 has the following characteristics:

Figure: Example of a volume with two plexes shows a mirrored volume, vol06, with two data plexes.

Figure: Example of a volume with two plexes

Example of a volume with two plexes

Each plex of the mirror contains a complete copy of the volume data.

The volume vol06 has the following characteristics:

VxVM supports the concept of layered volumes in which subdisks can contain volumes.

More Information

Mirroring (RAID-1)

Layered volumes