Thanks to a report from Wired, we now know that the mini-datacenter (code named Sub-Zero) that Facebook is building as an add-on to their existing Oregon datacenter campus, will be dedicated to datacenter backup. According to the report, Facebook will use a new type of low-power deep storage device that doesn’t currently exist.
Facebook is apparently setting their engineering staff on the task of designing what sounds like an on-demand backup system, that, when quiescent, is powered down and the datacenter housing it will be optimized to support this type of operation. Facebook currently uses a disk-to-disk backup process, with one live copy and one archival copy of the data created. This is a fairly common backup process, and Facebook skips what is often the final step. There is no move to tape storage as the ultimate archival target.