Novell SUSE LINUX ENTERPRISE SERVER 10 SP2 HEARTBEAT Manual page 182

Distributed replicated block device (drbd)
DRBD is a block device designed for building high availability clusters. The whole
block device is mirrored via a dedicated network and is seen as a network RAID-
1.
failover
Occurs when a resource or node fails on one machine and the affected resources
are started on another node.
fencing
Describes the concept of preventing access to a shared resource by non-cluster
members. It can be archived by killing (shutting down) a "misbehaving" node to
prevent it from causing trouble, locking resources away from a node whose status
is uncertain, or in several other ways. Furthermore fencing is distinguished between
node and resource fencing.
Heartbeat resource agent
Heartbeat resource agents were widely used with Heartbeat version 1. Their use is
deprecated, but still supported in version 2. A Heartbeat resource agent can perform
start, stop, and status operations and resides under /etc/ha.d/
resource.d or /etc/init.d. For more information about Heartbeat resource
agents, refer to http://www.linux-ha.org/HeartbeatResourceAgent.
local resource manager (LRM)
The local resource manager (LRM) is responsible for performing operations on
resources. It uses the resource agent scripts to carry out the work. The LRM is
"dumb" in that it does not know of any policy by itself. It needs the DC to tell it
what to do.
LSB resource agent
LSB resource agents are standard LSB init scripts. LSB init scripts are not limited
to use in a high availability context. Any LSB-compliant Linux system uses LSB
init scripts to control services. Any LSB resource agent supports a start, stop,
restart, status and force-reload option and may optionally provide
try-restart and reload as well. LSB resource agents are located in /etc/
init.d. Find more information about LSB resource agents and the actual speci-
fication at
http://www.linux-foundation.org/spec/refspecs/LSB_3.0
.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
174 Heartbeat
http://www.linux-ha.org/LSBResourceAgent
and