VERITAS Volume Manager 4.1 Administrator's Guide

Understanding VERITAS Volume Manager
How VxVM Handles Storage Management
Chapter 16
Data can be spread across several disks within an array to distribute or
balance I/O operations across the disks. Using parallel I/O across
multiple disks in this way improves I/O performance by increasing data
transfer speed and overall throughput for the array.
Figure 1-2 How VxVM Presents the Disks in a Disk Array as Volumes to the
Operating System
Multipathed Disk Arrays
Some disk arrays provide multiple ports to access their disk devices.
These ports, coupled with the host bus adaptor (HBA) controller and any
data bus or I/O processor local to the array, make up multiple hardware
paths to access the disk devices. Such disk arrays are called multipathed
disk arrays. This type of disk array can be connected to host systems in
many different configurations, (such as multiple ports connected to
different controllers on a single host, chaining of the ports through a
single controller on a host, or ports connected to different hosts
simultaneously). For more detailed information, see Chapter 3,
“Administering Dynamic Multipathing (DMP),” on page 109.
Disk 4Disk 3Disk 2
Volumes
Operating System
Physical Disks
VERITAS Volume Manager
Disk 1