Bitcoin mining hashrate hit 1 PH today, five weeks earlier than I predicted. Ouch.
As penance, I’m going to visualize one petahash using asicminer hardware as a starting point.
An Asicminer Blade is 10GH, so 1 PH is 100,000 of these.
This is Gen 1 / 110nm hardware, pretty much bottom of the line for asics, which will throw off our scenario by a constant factor. Judging by the hardware specs of
when the bitcoin mining network has everything running on 28nm asics, there could be a 10x increase in KW/GH efficiency. There won’t be much efficiency gains past the 28nm chips for a while, and when the smaller chips finally come the gains will be modest. At any rate, Gen 1 Blades are the only hardware that is shipping today and I’m fairly familiar with this form factor, so starting with that.
What would 100,000 blades look like racked and stacked? Turn to the top picture, which is a 10 blade subrack, or 100GH. Bigger picture of pretty much the same thing, here:
Subrack looks like about 7Us, and a typical rack is 42Us, so 6 subracks to a rack. 600 GH/rack.
5 to 10 racks is a row. In the schematic below, taken pretty much at random from an energystar infovert, we get 7 racks to a row and 3 rows. You stack rows with the hot ends blowing against each other so you get a cold / hot / cold pattern when you walk around in the computer room.
This room has 3 7-row racks. 21 racks is 12,600 GH. 1.26TH. And at 25 feet per rack, about 500 square feet.
As a side note, another direction to go here with form factors is shipping container. Data center in a shipping container is sexy. But in 2013 it seems pretty pie in the sky. We’ll stick to typical rooms in a data center. Maybe shipping containers another day.
Anyway it is loud in this room, like standing a hundred feet away from a jet engine. All those fans. Loud, and if you don’t have air conditioning, it gets hot. When it gets too hot, your mining rigs start switching off, or if you’re unlucky and don’t have good failsafes they just flat out hardware fail and stop working forever.
Time to think about power and cooling. Blades are 0.007KW/GH but let’s triple that to add some CRAC (Computer Room Air Conditioning). 0.021 KW/GH. 15 KW/rack. About 26 KW in our little room.
I don’t know whether 26 KW in our room is realistic. Mining is unusual, because all the racks are blasting close to full power all the time. Maybe you can’t fit that many racks in a room, and keep them cool, with typical data center power arrangements. Maybe the most cost efficient way to scale up your mining operation is to keep the rooms largely empty, while you scout around for high power density with affordable rent. But let’s ignore that for now.
Let’s imagine we are filling up One Wilshire, a famous 30 story data center in Los Angeles. Let’s say there is enough power and cooling, and we are really packing our mining equipment in.
Maybe thirty above-described rooms per story. Not every story is data center — there are lawyers and acountants who rent there too — but ignore that. So, 900 possible rooms, and 30 rooms per story. 37.8 TH/story. 1.1 PH/building.
We have our answer. The bitcoin mining network run on Gen 1 hardware consists of about one One Wilshire-sized data center filled with Blades. Somewhat confirmatory of our ballpark estimate, One Wilshire sold for 437.5 million dollars last month.
If we had this running on gen 2 hardware, one petahash would be 3 stories and the entire building would be 10 petahashes.
Either way, our building sized mine would consume 21 megawatts of power, with one third for hashing and two thirds for cooling.
And that is what one petahash (or ten petahashes of gen 2) looks like.