Another thing with metadata being stored as enormous amount of files is that we will be unable to use readahead(2) facility - too many files to cache, too small files and the gain of readahead in this case is close to zero. Having it all in one file might speed-up the syncdaemon startup, since ureadahead profiling might find out that we are loading such file on startup and cache it e.g. during/before gdm login.
Another thing with metadata being stored as enormous amount of files is that we will be unable to use readahead(2) facility - too many files to cache, too small files and the gain of readahead in this case is close to zero. Having it all in one file might speed-up the syncdaemon startup, since ureadahead profiling might find out that we are loading such file on startup and cache it e.g. during/before gdm login.