VERITAS Volume Manager 3.1 Administrator's Guide

Introduction to Volume Manager
Volume Administration Tasks
Chapter 164
Volume Administration Tasks
Volume Manager can be used to perform system and configuration
management tasks on its objects: disks, disk groups, subdisks, plexes,
and volumes. Volumes contain two types of objects:
• subdisk—a region of a physical disk
• plex—a series of subdisks linked together in an address space
Disks and disk groups must be initialized and defined to the Volume
Manager before volumes can be created. Volumes can be created in
either of the following ways:
Automatically—you can create and manipulate volumes by using the
vxassist command. The vxassist command creates required plexes
and subdisks by using only the basic attributes of the desired volume
as input. The vxassist command can also modify existing volumes.
It automatically modifies any underlying or associated objects.The
vxassist command uses default values for many volume attributes,
unless you provide specific values.
Manually—you can create volumes by first creating the volume
subdisks, then the plexes, then the volume itself (a bottom-up
approach). This approach often requires detailed user input and an
understanding of Volume Manager concepts. Creating volumes
manually is useful for manipulating volumes with specific,
non-default attributes. The manual approach does not use the
vxassist command.
NOTE This section focuses on how to create and modify volumes using the
manual “bottom-up” approach. However, it can be more convenientto use
the automated vxassist command approach to volume management.
Many of the concepts and procedures in this section are normally
“hidden” from the casual user. Some procedures are managed
automatically by higher level commands such as the vxassist
command. Some of the commands and procedures described are not
normally performed by system administrators.
The steps normally involved in creating volumes manually are: