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

Chapter 12: Configure Device Monitors 121
After the gateway device monitor is configured on a server, it pings the
gateway device periodically. If a network failure occurs and the ping
fails, any active virtual hosts on the server will become inactive and fail
over to another server.
Custom Device Monitor
A CUSTOM device monitor can be used when the built-in DISK type is not
sufficient. Custom device monitors can be particularly useful when
integrating HP Clustered File System with a custom application.
HP Clustered File System treats custom monitors just as it does the built-
in
DISK monitor, except that you must supply the probe script. In the
script, probe commands should determine the health of the device as
necessary. If the device is operating normally, the probe script should exit
with exit status zero. If the device is not operating normally, the probe
script should exit with a non-zero exit status. HP Clustered File System
interprets the non-zero exit status as a failure of the device and takes the
appropriate action.
See “Advanced Topics” on page 146 for information about developing
probe scripts for custom monitors and integrating monitors with custom
applications.
Server Assignments
When you configure a device monitor, you can specify the servers to
which it should be assigned.
•A
DISK monitor that checks access to a SAN disk partition should be
assigned to all servers having virtual hosts associated with
applications that access data from the filesystem.
•A
DISK monitor for a local drive is typically configured for a single
server, meaning that a private device is being monitored and the
device monitor configuration is unique to a particular server.
•
GATEWAY monitors are multi-active and can be assigned to multiple
servers.
•
CUSTOM monitors can be assigned to one or more servers as
appropriate for the monitor.