Out of curiosity, what was the use case/upstream requirement for building Kivaloo in the first place?

The Kivaloo page notes that it was designed for Tarsnap, but I'm curious as to the "why" - eg, an eventual-consistency/consensus building block, a simple local metadata service, server-side housekeeping...?

(I'm also curious what "{indexed ,}sorted files" means, and how UFS is significant.)