https://github.com/bitcoin/bitcoin/pull/12653
a1926362e -blocksdir: keep blockindex leveldb database in datadir f38e4fdb0 QA: Add -blocksdir test 386a6b62a Allow to optional specify the directory for the blocks storage
Original PR was buggy though, hence:
bugfix PR15124 (Ben Woosley) ba8c8b2227 Fail if either disk space check fails
Also consider these related ones:
- https://github.com/bitcoin/bitcoin/pull/14364 (clarify the help message for blocksdir; as of now unmerged)
- https://github.com/bitcoin/bitcoin/pull/14374 (qt info)