I like the way you phrase the question, as normally I hear networked storage including SAN and NAS benefits and justification centered on business benefits tied to data and storage management. In other words, the usual rhetoric is that data and storage management can be improved by using SAN and/or NAS. Benefits to data storage management that are driving SAN and NAS adoption include enhanced connectivity, device sharing, data sharing with NAS, shared backup, potential for performance improvements and resiliency. Networked storage in general supports scaling of availability, performance and capacity compared to direct attached architectures.
There are the arguable added complexities of a networked storage environment using SAN or NAS compared to a DAS environment. The added complexities of a networked storage environment compared to DAS need to be evaluated on a scaling basis. For example, a couple of servers with SAS or SATA direct attached storage for a file server compared to several dozen servers accessing a Windows file or NAS server or compared to hundreds of servers accessing a shared iSCSI or Fibre Channel SAN.
Look at the number of servers you have, how much storage do you need and how much data needs to be shared. Also take a look at what your application and data availability and performance requirements are. Factor these among other attributes to decide if you need DAS or some form of networked storage.
This was first published in January 2007