No way! We are disk I/O limited right now. We think we can approximately double our performance simply by using SSDs instead of traditional 7200 RPM drives. I'm advocating for building an "SSD Pod" built with 1 or 2 TByte SSDs.
> and a very small portion of the data on on the spindles being needed at any given moment
With our original Personal Backup product that was true. Everybody was happy with waiting a few hours for their restores to complete. But with our new product line of B2 (competes with Amazon S3) then suddenly performance can matter much more, because programmers using B2 might be implementing all sorts of different access patterns. If those programmers are using B2 to implement online backup, then yes, still fine. But if the programmers are building hacker news or reddit or Dropbox the access patterns might require faster IOPS to be more responsive.