dataStore check is too slow
Currently to check data files integrity we read all files and make a md5 checksum of the contents.
This takes a hell lot of place in memory and proves to be quite slow (takes some long seconds of boot-up time)
We could avoid that by instead using readDir with file info and add all files with their sizes and modified date/time to get a clear 'photo' of data files and know for sure if we need to ergen or not.