VERITAS Volume Manager 4.1 Migration Guide

VxVM and LVM
Introducing the VERITAS Volume Manager
Chapter 12
• The VERITAS Volume Manager is integrated with HP MC/ServiceGuard and
ServiceGuard OPS Edition for High Availability, but requires a specific version of the
ServiceGuard products. Refer to the VERITAS Volume Manager Release Notes for details
about the required version number, as well as the availability of specific features in your
release.
Notable Features of VxVM
The VERITAS Volume Manager provides many features, some of which are not available with
LVM or MirrorDisk/UX. Notable VxVM features are described in the list below. See VERITAS
Volume Manager Release Notes for a more detailed list of features available in each VERITAS
Volume Manager product. See the other VERITAS Volume Manager documents (see “Related
Documentation” on page 7 in "Preface") for more details about these features.
VERITAS Volume Manager includes the following features:
• Concatenation, the combining of discontiguous disk regions into virtual devices.
• Spanning, concatenation across different physical media.
• Striping, distribution of storage mappings for a virtual device so that multi-threaded
accesses tend to cause even use of all physical media.
• The VERITAS Enterprise AdministratorTM (VEATM), a JAVA-based GUI for VxVM.
• Dynamic Multipathing (DMP) for active-passive devices, such as FC60. DMP provides
higher availability to data on disks with multiple host-to-device pathways by providing a
disk/device path failover mechanism. In the event of a loss of one connection to a disk, the
system continues to access the data over the other available connections to the disk.
• Free Space Management, providing simple goal-based allocation of storage.
• Task Monitor, which tracks the progress of system recovery by monitoring task creation,
maintenance, and completion. The Task Monitor allows you to pause, resume, and stop as
desired to adjust the impact on system performance.
• Dynamic Multipathing (DMP) for active-active devices, such as HP Surestore Disk Array
xp256, HP Surestore Disk System FC10 and other disk devices. DMP provides higher
availability to data on disks with multiple host-to-device pathways by providing a
disk/device path failover mechanism. In the event of a loss of one connection to a disk, the
system continues to access the data over the other available connections to the disk. DMP
also provides in some cases, improved I/O performance from disks with multiple
concurrently available pathways by balancing the I/O load uniformly across multiple I/O
paths to the disk device. LVM supports path failover but does not support I/O balancing.