4.1 Reliability Scalable Cluster Technology

Reliable Scalable Cluster Technology (RSCT) is a product that is fully integrated into TSA. RSCT is a set of software products that provides a comprehensive clustering environment for AIX® and Linux®. RSCT provides clusters with improved system availability, scalability, and ease of use. RSCT provides several basic components, or layers, of functionality:

Resource Monitoring and Control provides global access for configuring, monitoring, and controlling resources in a peer domain.

RMC is the scalable, reliable backbone of RSCT. It runs on a single system or on each node of a cluster, providing a common abstraction for the resources of the cluster. In a cluster, the RMC framework allows a process on any node to perform an operation on one or more resources on any other node inside the cluster.

As the name implies, RMC monitors resources (disk space, CPU usage, processor status, application processes, and so on) and controls the system by performing actions in response to defined conditions.

There is a core set of resource managers provided by RSCT, and additional resource managers are provided by CSM for AIX and CSM for Linux. Resource managers provide low-level instrumentation and control, or act as a foundation for management applications. The following are the core resource managers of RSCT:
Audit Log resource manager
Configuration resource manager
Event resource manager
File System resource manager
Host resource manager
Sensor resource manager

  • Cluster Security Services (CtSec)

Cluster Security Services is a new security infrastructure that is used by RMC to authenticate a node within the cluster, verifying that the node is who it says it is. This is not to be confused with authorization (granting or denying access to resources), which is handled by RMC.

CtSec uses credential-based authentication that enables:
A client process to present information to the server that owns the resource to be accessed in a way that cannot be imitated.
A server process to clearly identify the client and the validity of the information.
Credential-based authentication uses a third party that both the client and the server trust. In this release, only UNIX® host-based authentication is supported.

  • High Availability Group Services (HAGS) is a distributed coordination, messaging, and synchronization service.

  • High Availability Topology Services (HATS) provides a scalable heartbeat for adapter and node failure detection, and a reliable messaging service in a peer domain.

For more information about RSCT, see the IBM Cluster Information Center:

http://publib.boulder.ibm.com/infocenter/clresctr/vxrx/index.jsp?topic=/com.ibm.cluster.rsct.doc/rsctbooks.html
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