• In terms of performance, also keep in mind that not all SAN's are created equal.  A former employer switched from one brand to another (Xiotech to EMC) and immediately we noticed a 20% - 25% improvement in out IO throughput.  The increase was large enough to be very noticable to our users. 

    Of course the improvement was anything but free.  Both there and at my current employer we calculate the cost of the EMC storage to be $220 per GB!  Certainly not cheap.  But in a little more than six years combined usage neither company has ever experienced data loss due to system failure.  That, in my opinion, is the real reason to use a good SAN.

    /*****************

    If most people are not willing to see the difficulty, this is mainly because, consciously or unconsciously, they assume that it will be they who will settle these questions for the others, and because they are convinced of their own capacity to do this. -Friedrich August von Hayek

    *****************/