HP Serviceguard Version A.11.19 Release Notes, October 2009

See also “cmappmgr” (page 32).
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://docs.hp.com ->
HP Virtual Server Environment (VSE) -> HP Integrity Virtual
Machines.
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.11.19 49