On Sat, Mar 12, 2011 at 4:04 PM, Alain Spineux <aspineux at gmail.com> wrote: > Thanks to everybody for answering. > > I thing >250E6 is a lot and keep decent read and write access speed is unreal > using mutli-purpose filesystems like ext? and other ?FS. > I would need a dedicated filesystem for that. > > This problem was only a possible solution to another problem. > I will solve the original problem using another way. > Why, exactly, are you doing this? The normal approach for such dense repositories is to create a hierarchy of subdirectories. File aaa12345 goes in $DIR/a/a/a/12345 File abc6789 goes in $DIR/a/b/c/6789 And whatever is accessing or creating the files is taught the algorithm used. This requires some programming up front, but helps prevent precisely the outrageous directory size you describe. Handling, sorting, and reporting on that many files in one directory is an old and painful problem.