IBM SG24-5131-00 User Manual

Page of 240
200
 
IBM Certification Study Guide  AIX HACMP
handling membership and event management by using heartbeats. On the 
SP, the original High Availability infrastructure was built on this technology, 
and HACMP/ES Version 4.3. is now another instance relying on it. As of AIX 
4.3.2 and PSSP 3.1, the High Availability infrastructure, which previously was 
tightly coupled to PSSP, was externalized into a package called RISC System 
Cluster Technology (RSCT). This package can be installed and run, not only 
on SP nodes, but also on regular RS/6000 systems. This allows HACMP/ES 
to also be available on non-SP RS/6000s as of Version 4.3.
10.2.1  IBM RISC System Cluster Technology (RSCT)
The High Availability services previously packaged with the IBM PSSP for 
AIX Availability Services, also known as the ssp.ha fileset, are now an 
integral part of the HACMP/ES software. The IBM RS/6000 Cluster 
Technology (RSCT) services provide greater scalability, notify distributed 
subsystems of software failure, and coordinate recovery and synchronization 
among all subsystems in the software stack.
Packaging these services with HACMP/ES makes it possible to run this 
software on all RS/6000s, not just on SP nodes.
RSCT Services include the following components:
Event Manager 
A distributed subsystem providing a set of high 
availability services. It creates events by matching 
information about the state of system resources with 
information about resource conditions of interest to 
client programs. Client programs, in turn, can use event 
notifications to trigger recovery from system failures.
Group Services 
A system-wide, fault-tolerant, and highly available 
facility for coordinating and monitoring changes to the 
state of an application running on a set of nodes. Group 
Services helps both in the design and implementation of 
fault-tolerant applications and in the consistent recovery 
of multiple applications. It accomplishes these two 
distinct tasks in an integrated framework.
Topology Service
A facility for generating heartbeats over multiple 
networks and for providing information about adapter 
membership, node membership, and routing. Adapter 
and node membership provide indications of adapter 
and node failures respectively. Reliable Messaging uses 
the routing information to route messages between 
nodes around adapter failures.