| If even if reitzensteinm was talking about capacity-per-watt, he's still wrong. The specific drive he mentioned was the "Raptor" model but that's an old, slow, small (150G) and power hungry (9.5W) disk. The newer WD "VelociRaptor" 10K RPM disk is more likely what he meant, and is a more fair comparison. The new Velociraptor only has a 600 GB capacity. The highest capacity OCD IBIS drive is 960 GB. http://www.wdc.com/en/products/Products.asp?DriveID=821
http://www.ocztechnology.com/products/solid-state-drives/hsd... OCD IBIS Power:
6.6 Watts Idle
9.5 Watts Active WD VelociRaptor Power:
4.30 Watts Idle
6.20 Watts Active Now we do the math. A total of 9600 GB would be 10 OCD disk or 16 VelociRaptor disk. 16 x 6.20 = 99.2 --WD VelociRaptor 10 x 9.5 = 95 --OCD IBIS Similar is true for idle. If we were not limited to VelociRaptor, when you get into some of the very slow but very huge disks (1-2 TB), sure, you could beat the rather specific OCD IBIS models on Capacity-Per-Watt. But it is very unfair to open only one side of the rotating vs. ssd comparison to every disk made, and there are higher capacity SSD's with even better power consumption numbers than the OCD IBIS. As you noted, the metric of Cost-Per-Capacity is often 10 or more times more favorable for rotating disks. If you don't have a valid _need_ for the speed offered by SSDs, they are certainly not worth the added costs. |
It was not my intent to be argumentative - I just read your post and thought, power consumption as a benefit, are you sure you've done the math on this?
By the way, I couldn't find any 2 TB drives that were not PCI-X, so I do stand by my original analysis. With 1 TB SSDs, you'll still need 2x the servers. If you can piece together an SSD solution, ignoring cost, and including server wattage that can beat out an array of 2 TB drives on wattage, I will retract my original statement. You can use the idle power as the active power for the drives.