Installation guide

you can match the number of nodes according to load requirements. If a node in a load-balancing

cluster becomes inoperative, the load-balancing software detects the failure and redirects requests to

other cluster nodes. Node failures in a load-balancing cluster are not visible from clients outside the

cluster. Red Hat Cluster Suite provides load-balancing through LVS (Linux Virtual Server).

High-performance clusters use cluster nodes to perform concurrent calculations. A high-performance

cluster allows applications to work in parallel, therefore enhancing the performance of the

applications. (High performance clusters are also referred to as computational clusters or grid

computing.)

Note

The cluster types summarized in the preceding text reflect basic configurations; your needs

might require a combination of the clusters described.

1.2. Red Hat Clust er Suit e Int roduct ion

Red Hat Cluster Suite (RHCS) is an integrated set of software components that can be deployed in a

variety of configurations to suit your needs for performance, high-availability, load balancing,

scalability, file sharing, and economy.

RHCS consists of the following major components (refer to Figure 1.1, “ Red Hat Cluster Suite

Introduction” ):

Cluster infrastructure — Provides fundamental functions for nodes to work together as a cluster:

configuration-file management, membership management, lock management, and fencing.

High-availability Service Management — Provides failover of services from one cluster node to

another in case a node becomes inoperative.

Cluster administration tools — Configuration and management tools for setting up, configuring,

and managing a Red Hat cluster. The tools are for use with the Cluster Infrastructure components,

the High-availability and Service Management components, and storage.

Linux Virtual Server (LVS) — Routing software that provides IP-Load-balancing. LVS runs in a

pair of redundant servers that distributes client requests evenly to real servers that are behind the

LVS servers.

You can supplement Red Hat Cluster Suite with the following components, which are part of an

optional package (and not part of Red Hat Cluster Suite):

GFS — GFS (Global File System) or GFS2 (Global File System 2) provides a cluster file system for

use with Red Hat Cluster Suite. GFS/GFS2 allows multiple nodes to share storage at a block level

as if the storage were connected locally to each cluster node.

Cluster Logical Volume Manager (CLVM) — Provides volume management of cluster storage.

Note

When you create or modify a CLVM volume for a clustered environment, you must ensure

that you are running the clvmd daemon. For further information, refer to Section 1.6,

“ Cluster Logical Volume Manager”.

⁠Chapt er 1 . Red Hat Clust er Suit e Overview