3.5.1 Matrix Server Administration Guide

Chapter 1: Introduction 10

the same filesystem exports) regardless of any failover transitions, from

one node to another, of the Virtual NFS Service.

Virtual Hosts and Failover Protection

Matrix Server uses virtual hosts to provide failover protection for servers

and network applications.

A virtual host is a hostname/IP address configured on one or more servers.

The network interfaces selected on those servers to participate in the

virtual host must be on the same subnet. One server is selected as the

primary server for the virtual host. The remaining servers are backups.

The primary and backup servers do not need to be dedicated to these

activities; all servers can support other independent functions.

To ensure the availability of a virtual host, Matrix Server monitors the

health of all network interfaces and the health of the underlying server. If

you have created service or device monitors, those monitors periodically

check the health of the specified services or devices. If any of these health

checks fail, Matrix Server can transfer the virtual host to a backup server

and the network traffic will continue.

After creating virtual hosts, you will need to configure your network

applications to recognize them. When clients want to access a network

application, they use the virtual host address instead of the address of the

server where the application is running.

Service and Device Monitors

A service is a network service such as HTTP or FTP that is installed and

configured on the servers in the matrix. Matrix Server can be configured

to watch specific services with service monitors.

A service monitor is created on a virtual host. The service being

monitored should be installed on all servers associated with that virtual

host. When a service monitor determines that a service has failed, Matrix

Server transfers the virtual host for that service to a backup server. For

example, if the HTTP service fails, Matrix Server will transfer the HTTP

traffic to a backup server that provides HTTP.