When backing up and restoring tablespaces pgBackRest only operates on the subdirectory created for the version of PostgreSQL being run against. Since multiple versions can live in a tablespace (especially during a binary upgrade) this prevents too many files from being copied during a backup and other versions possibly being wiped out during a `--delta` restore. This only applies to PostgreSQL >= 9.0 -- before that only one PostgreSQL version could use a tablespace.
Most tests are working now. What's not working:
1) --target-resume option fails because pause_on_recovery setting was removed. Need to implement to the new 9.5 option and make that work with older versions in a consistent way.
2) No tests for the new .partial WAL segments that can be generated on timeline switch.