Oh for God’s sake. I cannot believe the HP guys, I mean 3PAR, are still selling this story. It’s the old scam where the real estate agent tries to get you into the four bedroom house you were looking for by taking you to this one:

3 Bedroom, 3 Bath, 1700 sq feet, clean. Should sell for 2X what it’s worth. Wait, I asked for a 4 bedroom, didn’t I?

Now hold on there pal, we have a story for you. By our calculations, you don’t really need that. In fact, we think if you were as clever as we are, you would have been able to meet your needs with a three bedroom. The fact is that the folks in your house all want more space than they need, and we’re smart enough to know that.

It turns out nobody ever plans and provisions bedrooms accurately, because everyone is a liar. Because of that, we will confidently move you into the three bedroom and we are confident that you won’t need the fourth bedroom. And, because we know this, we expect you to compare this 3 bedroom against four bedroom offers from people who aren’t as smart as we are.

OK, so I get a 3 bedroom house at a four bedroom price, and I have to ignore the fact that the 3 bedroom is a 3 bedroom. Got it.

Now, if Aunt Edna comes to stay, where does she go? Well, assuming the deal closes first, you just add on! All is well.

But I have to pay for the addition, right?

Sure, but look on the bright side. You already paid for part of what we didn’t give you in the first place for the thin housing license. And now you get to pay for the actual bedroom. It turns out that you ended up paying more using our thin housing thinking. After all, Aunt Edna takes up real space rather than thin space and the last time we made her sleep on the couch her lumbago acted up, making everyone miserable.

Well then why didn’t we just buy the fourth bedroom in the first place?

Well, that’s an easy one – because using thin thinking, we avoided the unnecessary cost!

I hope that is clear to everyone. If you only need 3 bedrooms, shop for four bedrooms, and let a real estate salesperson sell you a three bedroom at the same price! Why? Because you can always add on later! See?

Coming back around to storage of data instead of house guests and residents, have we all had just about enough of “Thin this and thin that”? Seems to me this would have worn out by now. If you need 100TB, you need 100TB, period. Thin provisioning may help you from having to buy 120 TB, but it cannot reduce the amount of storage you actually need. I will admit that 3Par has good thin features because they do. But they don’t make anywhere near the difference that the argument above would imply, since everyone these days has thin provisioning that does 95% of the same thing.

If you are buying storage, and some wise guy proposes you only really need 70TB, have everyone quote 70TB if you believe it. If you want to use the now universally-available thin provisioning feature to allocate 100TB, fine, do that too. Expect to get the performance provided by the 70TB worth of spindles, and to add capacity if Aunt Edna comes to stay.

Compare apples to apples, spindles to spindles, and TB’s to TB’s. I’m not sure if you can be too rich, but you can be too thin.