The point-of-sales system is the heartbeat of any retail operation. It provides critical ongoing access to the store's database of products, codes, names, and prices. If the point-of-sale system fails, cashiers cannot log sales and the operation loses money, customers, and its reputation for quality service.
In this case, clustering technology can deliver high system availability. The clustering solution would allow a pair of servers to access the multi-port storage devices (Disk Array) on which the database resides. In the event of a server failure on Server 1, the workload is automatically moved to Server 2 and end-users are switched over to the new server—with no operator intervention and minimal downtime. Note that the disk array itself can be protected by the fault-tolerant disk technology built into Windows NT Server. The addition of clustering technology means that the overall system remains online.
Figure 1: Retail branch before failure
Figure 2: Retail branch during failure