Quantifying SAN advantages
Although the benefits of SANs are obvious to storage administrators, quantifying them can be difficult. One recent study found savings of more than $600,000 a year by choosing a SAN over a conventional storage architecture.
The study, by the consulting firm Compass, focused on a network of 50 servers, 10 of which were running high availability applications, with a total of 5T Bytes of disk storage. Using a cost-and-service model developed by Compass, the study compared the costs of connecting the storage directly to the servers with a SAN. The savings came primarily from better utilization of storage hardware and fewer people needed to maintain and manage the storage system. Nearly half the savings ($300,000) came from cutting the number of people needed from five to two.
In addition, the more flexible SAN architecture produced significantly higher availability rates. The high-availability systems were down nearly two hours a month less with the SAN than the standard configuration and the normal availability systems were down nearly six hours a month less.
However, the model did not include the additional cost of the SAN hardware, nor did it attempt to estimate the savings from decreased downtime or faster data access. The report is available in .pdf format at the Compass website.
Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last twenty years he has been a freelance writer specializing in storage and other computer issues.