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

Chapter 12: Configure Device Monitors 120
For example, if a probe fails on the primary server for a virtual host, the
virtual host may fail over to a backup server. See “Device Monitors and
Failover” on page 122 for details about where a device monitor is active.
DISK Device Monitor
A DISK device monitor periodically attempts to read the first block of the
disk partition that you specify. You can use this monitor to determine
whether a server can access a SAN partition containing a PSFS filesystem.
This monitor is multi-active and will probe on all servers on which it is
configured.
When you create a
DISK monitor, be sure to configure the following
advanced options:
• Virtual hosts. Select any virtual hosts that should fail over if the
monitor probe cannot access the partition. Typically these virtual
hosts are associated with applications that access data on the PSFS
filesystem.
• Servers. Select the servers providing the above virtual hosts.
A DISK device monitor can also be used to watch a local drive on a
server.
GATEWAY Device Monitor
When certain network failures occur, the servers in a cluster can lose
communication with each other. This situation can result in a partition, or
split, of the cluster. For example, in a two-server cluster, each server
would assume that it remained in the cluster and that the other server
was down. The gateway device monitor detects the network failure and
prevents the cluster from partitioning. A gateway device monitor is
multi-active and can be configured on multiple servers.
When you configure the monitor, you will be asked for the network
address of a router or other gateway probe device. The IP address of the
device should be on a different subnet than the servers in the cluster. The
device should respond to a ping and should be visible on each server.