I was wondering how much storage people are putting behind their storage heads ?

I can see that a 3170 nominally goes up to 840TB or 420 per head but do people actually put that much storage on a single unit ?

I can see that the V series supports SVC, how common is this configuration ?

We need to be aiming for about a half Petabyte per rack, I can see how I could do this with a DDN S2A9900 behind an SVC, I would be interested to hear peoples opinion.