I will read this tonight. I have a meeting with Drobo tomorrow and I think this is the same article on of their guys sent me. -- Jason T. Slack-Moehrle On Wednesday, January 25, 2012 at 5:37 PM, aurfalien wrote: > On Jan 25, 2012, at 4:50 PM, John R Pierce wrote: > > > On 01/25/12 4:27 PM, Jason T. Slack-Moehrle wrote: > > > can you explain to the calculation to determine that 300gb is 2mbps? > > > > > > > > 300GB (big B for byte) / 30 days / 24 hours/day / 3600 seconds/hour, > > and > > I get 0.12MB/second, so multiplying by 10 to get bits allowing for > > basic > > protocol overhead, I come up with 1.2Mbit/sec sustained average. > > > > > > 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. > > > > are you serious? > > Nice analysis. > > Yea the heat footprint alone will require some good AC. I'm open > minded and am intrigued on who this will be pulled off but still, > sounds crazy and not too well thought out. > > I do like the not for profit spin which helps the cause out. > > A quick search found this; > > http://bioteam.net/2011/08/why-you-should-never-build-a-backblaze-pod/ > > Basically its a sort of why not to use a backBlaze but we sort did ... > > - aurf > _______________________________________________ > CentOS mailing list > CentOS at centos.org (mailto:CentOS at centos.org) > http://lists.centos.org/mailman/listinfo/centos