HP ProLiant DL380G5-WSS 3.7.0 HP StorageWorks HP Scalable NAS File Serving Sof - Page 77
Con servers for DNS load balancing
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name of the server to the virtual host, which is generally the better solution, or keep the published name associated with the server. • Migrate the existing server name to a virtual hostname. In this case, you will need to assign a new name to the server. External sites that then access the original server name will actually be served by the virtual host-basically, a failover-protected version of the server, with no difference in appearance to the clients. • 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 Scalable NAS. If the server fails, requests to the server's hostname fail, whereas requests to the new virtual hostname are automatically redirected by HP Scalable NAS to a backup server. Configure servers for DNS load balancing HP Scalable NAS 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 Scalable NAS provides failover protection for this configuration. Without HP Scalable NAS, requests are simply alternated between the servers. If a server goes down, requests to that server do not connect. To configure round-robin load balancing with HP Scalable NAS, first define virtual hosts as addresses in the A records on the DNS. Then use HP Scalable NAS to associate primary and backup servers with that virtual host. In essence, you use the virtual host capability of HP Scalable NAS to accept the round-robin requests sent by the DNS. HP Scalable NAS 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. HP Scalable NAS File Serving Software administration guide 77