HP StorageWorks Clustered File System 3.2.1 Windows Storage Server Edition Administration Guide (February 2006)

Chapter 4: Configure Servers 34
• Keep the existing name on the server. If you do not rename the
server, clients will need to use the new virtual host name to benefit
from failover protection. Clients can still access the server by its name,
but those requests are not protected by HP Clustered File System. If
the server fails, requests to the server’s hostname fail, whereas
requests to the new virtual hostname are automatically redirected by
HP Clustered File System to a backup server.
Configure Servers for DNS Load Balancing
HP Clustered File System can provide failover protection for servers
configured to provide domain name service (DNS) load balancing. DNS
load balancing allows you to set up servers so that requests are sent
alternately to each of the servers in a cluster. For example, clients could
access acmd1 and acmd2 in turn, enabling the servers to share the load of
accepting and responding to client requests.
DNS includes a round-robin feature using address records (A records) to
alternate requests between IP addresses. This feature provides a
straightforward way to gain load balancing capability and simplified
load balancing, resulting in improved response time.
HP Clustered File System provides failover protection for this
configuration. Without HP Clustered File System, requests are simply
alternated between the servers. If a server goes down, requests to that
server do not connect.
To configure for round-robin load balancing with HP Clustered File
System, you define virtual hosts as addresses in the A records on the
DNS. Then use HP Clustered File System to associate primary and
backup servers with that virtual host. In essence, you use the virtual host
capability of HP Clustered File System to accept the round-robin requests
sent by the DNS. HP Clustered File System handles the failover function
to the real servers in the cluster.
In the following example, two servers, acmd1 and acmd2, are configured
to accept round-robin requests.