Red Hat Enterprise Linux ClusterRed 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:
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.
Red Hat Clustering is designed to run at a single physical site where latencies are expected to be LAN-like (under 2 msec). This remains the most recommended and rigorously tested configuration for running the Red Hat High Availability and Resilient Storage Add-Ons.
Stretch Clusters Stretch clusters are single-cluster configurations that span multiple physical sites.
Multi-Site Clusters Multi-site or disaster-tolerant clusters are separate clusters that run at different physical sites, typically using SAN-based storage replication to replicate data. Multi-site clusters are usually used in an active/passive manner for disaster recovery with manual failover of the active cluster to the passive cluster.