Tablespaces on tertiary media

Where does PostgreSQL stand with storing /really/ large amounts of data
offline? Specifically, if a FUSE is used to move a tablespace to something
like a tape archiver can the planner be warned that access might take an
extended period?

I know that at one point (v6?) there were hooks in the code for experimental
Berkeley code to do this sort of thing but as far as I know there has never
been anything publicly available.

--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]