To avoid confusion with other terms that describe volume management in general, EVMS uses a specific set of terms. These terms are listed, from most fundamental to most comprehensive, as follows:
Representation of anything EVMS can access as a physical disk. In EVMS, physical disks are logical disks.
The lowest level of addressability on a block device. This definition is in keeping with the standard meaning found in other management systems.
An ordered set of physically contiguous sectors residing on the same storage object. The general analogy for a segment is to a traditional disk partition, such as DOS or OS/2 ®
An ordered set of logically contiguous sectors that are not necessarily physically contiguous.
Any persistent memory structure in EVMS that can be used to build objects or create a volume. Storage object is a generic term for disks, segments, regions, and feature objects.
A collection of storage objects. A storage container consumes one set of storage objects and produces new storage objects. One common subset of storage containers is volume groups, such as AIX® or LVM.
Storage containers can be either of type private or cluster.
Specialized storage containers that consume only disk objects that are physically accessible from all nodes of a cluster.
A collection of disks that are physically accessible from all nodes of a cluster, managed as a single pool of storage, and owned and accessed by a single node of the cluster at any given time.
A collection of disks that are physically accessible from all nodes of a cluster, managed as a single pool of storage, and owned and accessed by all noDes of the cluster simultaneously.
A shared cluster container that is not owned by any node of the cluster.
A storage object that contains an EVMS native feature, such as bad block relocation.
An EVMS Native Feature is a function of volume management designed and implemented by EVMS. These features are not intended to be backwards compatible with other volume management technologies.
A volume that consumes a storage object and exports something mountable. There are two varieties of logical volumes: EVMS Volumes and Compatibility volumes.
EVMS Volumes contain EVMS native metadata and can support all EVMS features. /dev/evms/my_volume would be an example of an EVMS Volume.
Compatibility volumes do not contain any EVMS native metadata. Compatibility volumes are backward compatible to their particular scheme, but they cannot support EVMS features. /dev/evms/md/md0 would be an example of a compatibility volume.