It would be useful to implement this because separating data into a separate directory for each db is an important scaling technique for some customers.
Release Notes / 2.8 docs don't mention that WT doesn't support directoryperdb
storage engines without directoryperdb support should fail to start up with --directoryperdb
WiredTiger now supports directoryperdb
Remove storage.mmapv1.syncPeriodSecs and storage.wiredTiger.engineConfig.checkpointDelaySecs; use storage.syncPeriodSecs for both.
--directoryperdb under WiredTiger is not working