HP Serviceguard Version A.11.20 Release Notes, April 2011

Support for HP Integrity Virtual Machines (HPVM)
Serviceguard supports HP Integrity Virtual Machines (HPVM). HPVM runs only on HP Integrity
systems; it does not run on HP 9000 systems.
IMPORTANT: For the most up-to-date compatibility information, see the
Serviceguard/SGeRAC/SMS/Serviceguard Mgr Plug-in Compatibility and Feature Matrix, at
http://www.hp.com/go/hpux-serviceguard-docs —> HP Serviceguard, under the heading
General reference. See also the “Integrity VM/Serviceguard Support Matrix” in the white
paper Designing high-availability solutions with HP Serviceguard and HP Integrity Virtual Machines
on the same web page under White papers.
Serviceguard A.11.20 supports an HPVM either as a package or as a cluster node. If any
Serviceguard cluster node is a virtual machine, the amount of time Serviceguard needs to wait for
a failed node’s I/O to complete increases; see “About HPVM and Cluster Re-formation Time”
(page 33).
See also “About cmappmgr” (page 31).
About HPVM and Cluster Re-formation Time
When a node fails and the cluster re-forms, Serviceguard must wait a certain amount of time to
allow I/O from the failed node to be written out to the target storage device. Only after that time
has elapsed can Serviceguard allow an adoptive node access to that device; otherwise data
corruption could occur. The amount of time Serviceguard waits is calculated by Serviceguard and
is not user-configurable.
The above is true whether or not the cluster includes virtual machines (VMs), but using VMs as
Serviceguard nodes increases the amount of time Serviceguard needs to wait before it is safe to
allow another node access to the same storage. This additional wait can increase cluster re-formation
time by as much as 70 seconds.
The additional time Serviceguard needs to wait depends in part on whether or not a VM guest
depot is installed on the VM node. (See HP Integrity Virtual Machines Installation, Configuration,
and Administration, at the address given below, for information on installing a guest depot.)
Serviceguard uses information it derives from the VM guest depot to set the timeout to the optimal
value. If any VM node does not have a VM guest depot, Serviceguard may not be able to obtain
the information it needs to set the optimal timeout, and in that case it sets the additional timeout
to the maximum value, 70 seconds.
IMPORTANT: This additional timeout extension represents a net addition to the time it takes for
the cluster to re-form. For example, if the cluster typically took 40 seconds to re-form before any
VM nodes were added, it will take about 80 seconds when one or more VM nodes are members
of the cluster, if all those nodes have a VM guest depot. If any VM node without a VM guest depot
is a member of the cluster, it will take about 110 seconds. This is true whenever VM nodes are
cluster members, whether or not the re-formation is caused by the failure of a VM node.
For more information about HP Integrity Virtual Machines, see HP Integrity Virtual Machines
Installation, Configuration, and Administration at http://www.hp.com/go/hpux-hpvm-docs.
Access changes as of A.11.16
Serviceguard version A.11.16 introduced a new access method. As of A.11.16, Serviceguard
uses Access Control Policies, also known as Role-Based Access, rather than cmclnodelist or
.rhosts, to authenticate users.
For more information about Access Control Policies, see Chapter 5 of the Managing Serviceguard
manual, the Serviceguard Manager help, and the cluster and package configuration files themselves.
Features Introduced Before A.11.20 33