74 An Introduction to the New IBM Eserver pSeries High Performance Switch
3.1 RSCT Resource Monitoring and Control
RSCT (Reliable Scalable Cluster Technology) is a standard component of AIX that provides
the clustering infrastructure for the IBM Eserver Cluster 1600 suite of products. The RSCT
infrastructure contains the basic tools and architecture to build reliable and secure clustered
RSCT provides the foundation for the following applications:
IBM Virtual Shared Disk (VSD)
IBM General Parallel File System (GPFS)
IBM High Availability Cluster Multi-Processing (HACMP)
IBM LoadLeveler (LL)
IBM Eserver IBM Eserver pSeries High Performance Switch (HPS) network table
3.1.1 What is RSCT?
RSCT is a set of software components that work together to provide a comprehensive
clustering environment for AIX and Linux. RSCT is a component of AIX 5L derived from the
PSSP high-availability infrastructure.
The new IBM High Performance Computing (HPC) clusters provide a different approach from
the previous version (PSSP) in the sense that there is no more control workstation (CWS) nor
System Data Repository (SDR). Because of this, applications relying on the RSCT clustering
infrastructure must take a different approach for storing and managing their configuration
RSCT is the infrastructure used by a variety of IBM products to provide clusters with improved
system availability, scalability, and ease of use. RSCT is well proven to provide clustering
infrastructure for CSM, Distributed Resource Managers, HACMP, GPFS, and VSD, etc.
This chapter provides an overview of the RSCT components. It describes:
Resource Management and Control (RMC) subsystem
This is the scalable, reliable backbone of RSCT. It runs on a single machine or on each
node (operating system image) of a cluster and provides a common abstraction for the
resources of the individual system or the cluster of nodes. You can use RMC for single
system monitoring or for monitoring nodes in a cluster. RMC provides global access to
subsystems and resources throughout the cluster, thus providing a single monitoring and
management infrastructure for clusters.
RSCT core resource managers
A resource manager is a software layer between a resource (a hardware or software entity
that provides services to some other component) and RMC. A resource manager maps
programmatic abstractions in RMC into the actual calls and commands of a resource.
RSCT cluster security services
Provides the security infrastructure that enables RSCT components to authenticate the
identity of other parties.
Topology Services subsystem
The Topology Services subsystem is used within an RSCT peer domain to provide other
RSCT applications and subsystems with network adapter status, node connectivity
information, and a reliable messaging service. The Topology Services subsystem runs as
a separate daemon process on each machine (node) in the peer domain.