Glossary

525

An area of a disk under VxVM control that is not allocated to any subdisk or reserved for use by any other VxVM object.

free subdisk

A subdisk that is not associated with any plex and has an empty putil[0] field.

hostid

A string that identifies a host to VxVM. The hostid for a host is stored in its volboot file, and is used in defining ownership of disks and disk groups.

hot-relocation

A technique of automatically restoring redundancy and access to mirrored and RAID-5 volumes when a disk fails. This is done by relocating the affected subdisks to disks designated as spares and/or free space in the same disk group.

hot-swap

Refers to devices that can be removed from, or inserted into, a system without first turning off the power supply to the system.

initiating node

The node on which the system administrator is running a utility that requests a change to VxVM objects. This node initiates a volume reconfiguration.

JBOD

The common name for an unintelligent disk array which may, or may not, support the hot- swapping of disks. The name is derived from “just a bunch of disks.”

log plex

A plex used to store a RAID-5 log. The term log plex may also be used to refer to a Dirty Region Logging plex.

log subdisk

A subdisk that is used to store a dirty region log.

master node

A node that is designated by the software to coordinate certain VxVM operations in a cluster. Any node is capable of being the master node.

mastering node

The node to which a disk is attached. This is also known as a disk owner.

mirror

A duplicate copy of a volume and the data therein (in the form of an ordered collection of subdisks). Each mirror consists of one plex of the volume with which the mirror is associated.

mirroring

A layout technique that mirrors the contents of a volume onto multiple plexes. Each plex duplicates the data stored on the volume, but the plexes themselves may have different layouts.

multipathing

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HP Veritas Volume Manager 5.0 -UX 11i v3 manual Jbod