There are impressive technical and business advantages to consolidating servers and storage with SANs. A SAN infrastructure enables any-to-any connectivity between heterogeneous server and storage systems. This allows much more efficient use of storage and server resources by consolidating widely distributed or underutilized resource into centrally managed environments.

• Increase storage utilization by lowering allocation for headroom - unused storage that will used within one to two years
• Decrease storage capital expenditures by enabling the purchase of storage on an "as-needed" basis
• Increase administrative staff productivity - manage more storage with fewer personnel
• Reduce application downtime and minimize business impact for storage upgrades
• Create a centralized network environment for storage and server platforms

Traditionally, organizations have paired storage resources with specific servers, primarily because of technical restrictions. This implementation results in poor utilization of storage resources because the storage is dedicated to each server and not shared among servers. For example, free disk space on one server's disk subsystem cannot be used by other storage-constrained servers.

This paired server-device model has proven to be especially inflexible during periods of expansion. Simply adding more resources as requirements grow typically results in a very difficult environment to manage and poor utilization of resources. In addition, because organizations are having to buy a greater number of servers and storage devices, they tend to choose less expensive, slower, and less reliable ones.

To help avoid disruption and cost, SANs provide the advantages of flexible connectivity, more efficient use of storage resources, enhanced scalability, and increased manageability. In fact, SANs provide unprecedented flexibility for storage environments – changing the way storage resources can be purchased and managed. By enabling any-to-any server and storage connectivity via switches, SANs decouple dedicated devices and enable storage resource sharing. This cost-effective open systems approach enables the selection of best-of-breed heterogeneous equipment (see Figure 1).

Figure 1. A simplified best-of-breed SAN infrastructure with heterogeneous server and storage resources

SANs can help organizations grow their storage environments much more quickly because storage capacity can grow independent of server usage. This approach provides a high degree of efficiency in utilizing resources while simultaneously enabling growth without system disruption. For example, after deploying a SAN, a large hospital reduced the number of its primary Windows NT servers from 50 to just 7 with significantly improved automation and administration that lowered operating costs. In addition, a large telecommunications company that recently implemented a SAN was able to cut its previous storage requirements in half while reducing its server allocation by one-third.