How Many of What Disks?

The third and fourth major hardware questions are:

  • How much disk space?

  • What disk configuration?

These two questions should be resolved together. Gone for good are the days of just buying SCSI controllers and disks for servers. Today's data warehouses are far too big for that kind of solution—they must be built using disk arrays.

A disk array is a cabinet that houses front-end and back-end intelligent controllers, a sizable memory cache, and a very large disk farm (Figure 3-7). There are two kinds of disk arrays:

  • SAN

  • NAS

Figure 3-7. Basic Disk Farm Hardware Architecture

A SAN is a disk farm appliance. It's a shared, dedicated, ...

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