Reliable Scalable Cluster Technology (RSCT)
Reliable Scalable Cluster Technology (RSCT) is a product that is fully integrated into System Automation for Multiplatforms. RSCT is a set of software products that together provide a comprehensive clustering environment for AIX® and Linux®. System Automation for Multiplatforms uses the RSCT infrastructure to provide clusters with improved system availability, scalability, and ease of use.
The basic subsystems of RSCT are responsible for handling intracluster communication. This intracluster communication can use multiple communication channels. IP-based communication uses the network protocol User Datagram Protocol (UDP) and TCP/IP. Non-IP based communication writes to dedicated areas of a SCSI disk.
- RMC (Resource Monitoring and Control subsystem) :
- RMC is used for single-system monitoring and for monitoring nodes in a cluster. In a cluster, RMC provides global access to subsystems and resources throughout the cluster, thus providing a single monitoring and management infrastructure for clusters.
- HAGS (High Availability Group Services subsystem) :
- HAGS is a distributed coordination, messaging, and synchronization service. This service coordinates the recovery resource manager. The default intracluster communication protocol for HAGS is UDP.
- HATS (High Availability Topology Services subsystem):
- HATS provides a scalable heartbeat for adapter and node failure
detection, and a reliable messaging service in a peer domain.
The RSCT heartbeat mechanism performs a broadcast ping from time to time, especially when the availability of a network interface adapter cannot be determined. The purpose of this feature is to find out whether the network interface adapter that sends this broadcast ping is still operational (this can be determined according to whether other nodes reply to this broadcast ping or not). The default intracluster communication protocol for HATS is UDP.
- SRC (System Resource Controller) :
- The System Resource Controller (SRC) is the bootstrap process
that gets started first and starts all other daemon processes required
by RSCT and System Automation for Multiplatforms to
run. It is also responsible for restarting these daemon processes
on failure. The System Resource Controller provides a set of commands
and subroutines to make it easier for system managers to create and
control subsystems. The System Resource Controller is started from
the
inittab