Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

Chapter
1
Understanding Veritas
Volume Manager
Veritas
TM
Volume Manager (VxVM) by Symantec is a storage management subsystem
that allows you to manage physical disks as logical devices called volumes. A VxVM
volume appears to applications and the operating system as a physical disk on which file
systems, databases and other managed data objects can be configured.
VxVM provides easy-to-use online disk storage management for computing environments
and Storage Area Network (SAN) environments. By supporting the Redundant Array of
Independent Disks (RAID) model, VxVM can be configured to protect against disk and
hardware failure, and to increase I/O throughput. Additionally, VxVM provides features
that enhance fault tolerance and fast recovery from disk failure.
VxVM overcomes physical restrictions imposed by hardware disk devices by providing a
logical volume management layer. This allows volumes to span multiple disks.
VxVM provides the tools to improve performance and ensure data availability and
integrity. You can also use VxVM to dynamically configure disk storage while the system
is active.
The following sections of this chapter explain fundamental concepts of VxVM:
■ VxVM and the operating system
■ How VxVM handles storage management
■ Volume layouts in VxVM
The following sections introduce you to advanced features of VxVM:
■ Online relayout
■ Volume resynchronization
■ Dirty region logging
■ Volume snapshots
■ FastResync