> racking 2 PiB (or 2048TiB) of nearline grade storage will require about > 1000 3.5" 3TB drives, allowing for a reasonable raid level and suitable > number of hotspares. If its frequently updated transactional database > storage, I'd want to use raid10. Using somethign like the Supermicro > 847 chassis, you can get 36 drives plus a server in 4U, and draw about > 700 watts actual in use.... I estimate you'll want about 28 of these > servers, which will take two full racks and draw about 20KW, or 180 amps > off 120V household circuits (realistically, you'll need 208V for this > many servers). You'll also need about 10-15KW worth of air > conditioning equipment to deal with the generated 68000 BTUs of heat. > HVAC will push your power usage up to the 30-40kW range, or 2500 > KWH/month, at $0.20/KWH typical residential power usage, you're looking > at a $5000/month power bill, give or take. > > those 28 SuperMicro servers will cost about $200,000 for the 1000 3TB > enterprise nearline disks, plus another $200,000 or so for reasonably > well configured servers. 20KVA of redundant UPS and 70000 BTU worth of > computer room A/C will add a good chunk more $$$$ to this. Hi John, Yes, our (meaning yours and mine) calculations are different and I am probably wrong. I think I am drawn to the BackBlaze POD for reasons like this. 135TiB in a single enclosure and that is not even using 4TB drives. 2PiB is an estimate for the next 2 years, currently there is a little bit over 480TiB according to adding up various math calculations (databases, du, app data, static files, etc) I see your calculations about power and yes, currently power for just the UPS, Computers, fans and stuff runs me about $400 a month and I only have a few boxes handling the demo of the product. This will be my first summer in my new location in Cupertino and I know I will need to act on cooling really soon. Are you using Comcast in Santa Cruz? -Jason