I am planning to use LMDB to create a resonably large database, few TBs, > 500mil keys, on a Fusion IO flash storage.  Memory to storage ratio of the available hardware is about 1:10

Assuming the caching of "5 to 10%" of most-frequently-accessed data is good enough for my use-case, is this a valid/legitimate use of LMDB ? Or am I using the wrong tool for the job?

My other choices are RocksDB (haven't looked at it) or Postgres (using a limited subset of features), the latter mainly because we already use it across the company.

Any advice is appreciated.