This has been achieved by putting together 1920 harddrives at 500GB each. The first model of Symmetrix DMX-3 that has been launched now has "only" 960 harddrives with a capacity at 300GB (all together 288TB). They actually use a simpler version that rotates at 7200 rpm which means cheaper maintenance. We can surely guarantee that there will be at least one crash a month with over 1000 drives in one system.

Source: EMC