4.0.0 HP Polyserve Matrix Server Administration Guide (T5392-96052, March 2010)

• For a single-active monitor, the active virtual hosts are failed over to a backup
server and the monitor becomes active on that server. See the “Device Monitor
Activeness Policy,” below, for details about where the monitor will be made active.
• For a multi-active monitor, the virtual hosts are failed over to a backup server.
The monitor remains active on the same set of servers.
Device monitor activeness policy
ClusterPulse uses the following device monitor activeness policy to determine the
server or servers where it will make a device monitor active.
The device monitor activeness policy decision is made as follows:
1. If the device monitor on a specific server is disabled, then the device monitor
will not be made active on that server.
2. ClusterPulse considers the list of servers that are both up and enabled and that
are configured for the device monitor. Note the following:
• A server that has not finished joining the cluster (see “Server access to the
SAN” on page 241) is not considered up for the purpose of activating the
device monitor.
• A server is considered down if it loses coordinated communication with the
cluster (for example, the server crashed or was shut down, Matrix Server
was shut down on the server, the server failed to schedule a cluster group
communication process for an extended period of time).
3. If the device monitor is multi-active, it will be active on all servers passing evalu-
ation for steps 1 and 2. If the device monitor is single-active, then the list of
servers is filtered by the following policy items to determine the one server where
the device monitor will be active.
4. From the list of servers that pass evaluation for steps 1 and 2, ClusterPulse tries
to find a server with all services up and enabled on the virtual hosts associated
with this device monitor. If ClusterPulse finds a server meeting these conditions,
it will use it, preferring servers earlier in the list of servers for this device monitor.
5. If there are no servers with completely healthy services, ClusterPulse picks a
server that has at least one service up and enabled. If ClusterPulse finds a server
meeting these conditions, it will use it, preferring services earlier in the list of
servers for this device monitor.
6. If ClusterPulse cannot locate a server meeting these conditions, it will make the
device monitor active on the first server in the list of servers for this device mon-
itor.
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