VERITAS Volume Manager 3.1 Administrator's Guide

Introduction to Volume Manager
Volume Manager Conceptual Overview
Chapter 160
After installing Volume Manager on a host system, perform the following
procedure before you can configure and use Volume Manager objects:
• bring the contents of physical disks under Volume Manager control
bring the physical disk under VxVM control, the disk must not be
under LVM control. For more information on LVM and VxVM disk
co-existence or how to convert LVM disks to VxVM disks, see the
VERITAS Volume Manager Migration Guide.
• collect the Volume Manager disks into disk groups
• allocate the disk group space to create logical volumes
Bringing the contents of physical disks under Volume Manager
control is done only if:
• you allow Volume Manager to take control of the physical disks
• the disk is not under control of another storage manager
Volume Manager writes identification information on physical disks
under Volume Manager control (claimed disks). Claimed disks can be
identified even after physical disk disconnection or system outages.
Volume Manager can then re-form disk groups and logical objects to
provide failure detection and to speed system recovery.
Volume Manager and the Operating System
Volume Manager operates as a subsystem between your operating
system and your data management systems, such as file systems and
database management systems.
Before a disk can be brought under Volume Manager control, the disk
must be accessible through the operating system device interface.
Volume Manager is a subsystem layered on top of the operating system
interface services. Therefore, Volume Manager is dependent upon how
the operating system accesses physical disks.
Volume Manager is dependent upon the operating system for the
following.
• operating system (disk) devices
• device handles
• VM disks
• Volume Manager dynamic multipathing (DMP) metadevice