Manufacturers have been designing redundancy into their products for years in the form of redundant power supplies, multiple processors, segmented memory, and redundant disks. This can also refer to entire server systems running in a hot standby mode. Infrastructure analysts can take a similar approach by configuring disk and tape controllers, servers with dual paths, splitting network loads over dual lines, and providing alternate control consolesin short, eliminating as far as possible any single points of failure that could disrupt service availability.
The next three approachesreputation, reliability, and repairabilityare closely related. Reputation refers to the track record of key suppliers. Reliability pertains to the dependability of the components and coding that go into their products. Repairability is a measure of how quickly and easily suppliers can fix or replace failing parts. We'll look at each of these factors a bit more closely.
The reputation of key suppliers of servers, disk storage systems, database management systems, and network hardware and software plays a principal role in striving for high availability. It's always best to go with the best. Reputations can be verified in several ways. Percentage of market share is one measure. Another is reports from industry analysts and Wall Street. Track record in the field is a third. Customer references can be especially useful when confirming such factors as cost, service, product quality, training of service personnel, and trustworthiness.