Managing Serviceguard 13th Edition, February 2007

Understanding Serviceguard Software Components
Volume Managers for Data Storage
Chapter 3122
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 (B9116BA,
B9117BA), 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)
• do not have all nodes cabled to all disks. (required with CFS)
• need to use software RAID mirroring or striped mirroring.
• have multiple heartbeat subnets configured.
Propagation of Disk Groups in VxVM
With VxVM, a disk group can be created on any node, with the cluster up
or not. The user then needs to go to each node and validate that disk
group by trying to import it. Thus, although there are more steps
required for propagating disk groups with VxVM than with CVM (see
Cluster Volume Manager, CVM, below), you have the freedom to create
the disk group from any node.
Package Startup Time with VxVM
With VxVM, each disk group is imported by the package control script
that uses the disk group. This means that cluster startup time is not
affected, but individual package startup time might be increased because
VxVM imports the disk group at the time the package starts up.