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

Activity types for device monitors
The activity type specifies where the device monitor can be active. The activity type
can be one of the following:
• Single-Active. The monitor is active on only one of the selected servers. Upon
server failure, the monitor will fail over to an active server unless all associated
service and device monitors are down. (“Associated” service and device monitors
are those monitors that are associated with the same virtual host as this device
monitor.)
• Single-Always-Active. The monitor is active on only one of the selected servers.
Upon server failure, the monitor will fail over to an active server even if all asso-
ciated service and device monitors are down. (“Associated” service and device
monitors are those monitors that are associated with the same virtual host as this
device monitor.)
• Multi-Active. The monitor is active simultaneously on all servers configured for the
monitor.
By default, DISK, GATEWAY, and SHARED_FILESYSTEM monitors are multi-active.
This configuration allows the device monitor to probe a shared resource such as a
network gateway or a SAN partition containing a PSFS filesystem.
NTSERVICE and CUSTOM monitors can be either single-active or multi-active,
depending on the service or device being monitored.
Disk device monitor
A DISK device monitor can be used to watch a local drive on a server. It periodically
attempts to read the first block of the disk partition that you specify. This monitor is
multi-active by default and will probe on all servers on which it is configured.
If you want to monitor a PSFS filesystem on a SAN device, use a SHARED_FILESYSTEM
monitor instead of a DISK monitor.
GATEWAY device monitor
When certain network failures occur, the servers in a matrix can lose communication
with each other. This situation can result in a partition, or split, of the matrix. For
example, in a two-server matrix, each server would assume that it remained in the
matrix and that the other server was down. The gateway device monitor detects the
network failure and prevents the matrix from partitioning. A gateway device monitor
is multi-active and can be configured on multiple servers.
Configure device monitors218