Managing Serviceguard 14th Edition, June 2007

Understanding Serviceguard Software Components
Volume Managers for Data Storage
Chapter 3118
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)
• 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
“Veritas Cluster Volume Manager (CVM)” on page 119), 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.