HP StorageWorks Clustered File System 3.2.1 Windows Storage Server Edition Administration Guide (February 2006)

Chapter 10: Configure Virtual Hosts 99
• A server is considered down if it loses coordinated communication
with the cluster (for example, the server crashed or was shut down,
HP Clustered File System was shut down on that server, the server
failed to schedule a cluster group communication process for an
extended period of time, the server disabled the NIC being used
for cluster network traffic, and so on).
• The PanPulse process controls whether a network interface is
marked up or down. When PanPulse determines that an interface
currently hosting a virtual host is down, ClusterPulse will begin
searching for another server on which to locate the virtual host.
3. ClusterPulse narrows the list to those servers without inactive, down,
or disabled HP Clustered File System device monitors. If there are no
servers that meet this criteria, the virtual host is not made active
anywhere.
4. If the virtual host is currently active on a server and that virtual host
has the
NOFAILBACK policy, then this active server is moved to the
head of the list of preferred servers to be considered.
5. From this list, ClusterPulse tries to find a server with all services up
and enabled. If ClusterPulse finds a server meeting these conditions, it
will use it, preferring servers earlier in the list of servers configured
for the virtual host.
6. If there are no servers with completely healthy services, ClusterPulse
picks a server that has at least one service up and enabled. If the
services have different priorities, ClusterPulse uses a server where a
service with the highest available priority is up. If ClusterPulse finds a
server meeting these conditions, it will use it, preferring servers earlier
in the list of servers configured for the virtual host.
7. The selected server will have one interface that was configured for this
virtual host. The virtual host will be active on this interface. If
ClusterPulse cannot locate a server meeting these conditions, it does
not place the virtual host anywhere.