Managing Serviceguard Sixteenth Edition, March 2009

Types of Volume Manager
Serviceguard allows a choice of volume managers for data storage:
• HP-UX Logical Volume Manager (LVM) and (optionally) Mirrordisk/UX
• Veritas Volume Manager for HP-UX (VxVM)—Base and add-on Products
• Veritas Cluster Volume Manager for HP-UX
Separate sections in Chapters 5 and 6 explain how to configure cluster storage using
all of these volume managers. The rest of the present section explains some of the
differences among these available volume managers and offers suggestions about
appropriate choices for your cluster environment.
NOTE: The HP-UX Logical Volume Manager is described in the HP-UX System
Administrator’s Guide. Release Notes for Veritas Volume Manager contain a description
of Veritas volume management products.
HP-UX Logical Volume Manager (LVM)
Logical Volume Manager (LVM) is the default storage management product on HP-UX.
Included with the operating system, LVM is available on all cluster nodes. It supports
the use of Mirrordisk/UX, which is an add-on product that allows disk mirroring with
up to two mirrors (for a total of three copies of the data).
Currently, the HP-UX root disk can be configured as an LVM volume group. (Note
that, in this case, the HP-UX root disk is not the same as the Veritas root disk group,
rootdg, which must be configured in addition to the HP-UX root disk on any node
that uses Veritas Volume Manager 3.5 products. The rootdg is no longer required
with Veritas Volume Manager 4.1 and later products.) The Serviceguard cluster lock
disk also is configured using a disk configured in an LVM volume group.
LVM continues to be supported on HP-UX single systems and on Serviceguard clusters.
Veritas Volume Manager (VxVM)
The Base Veritas Volume Manager for HP-UX (Base-VxVM) is provided at no additional
cost with HP-UX 11i. This includes basic volume manager features, including a
Java-based GUI, known as VEA. It is possible to configure cluster storage for
Serviceguard with only Base-VXVM. However, only a limited set of features is available.
The add-on product, Veritas Volume Manager for HP-UX provides a full set of enhanced
volume manager capabilities in addition to basic volume management. This includes
features such as mirroring, dynamic multipathing for active/active storage devices,
and hot relocation.
VxVM can be used in clusters that:
• are of any size, up to 16 nodes.
• require a fast cluster startup time.
• do not require shared storage group activation. (required with CFS)
Volume Managers for Data Storage 113