Is it possible to setup an overlay style FS on Linux where the presence of a directory in the upper dir COMPLETELY overshadows the lower dir?
Lower Layer:
/dir1/fileA
/dir2/fileB
Upper Layer:
/dir1/fileC
/dir3/fileD
Desired Merge/Overlay has no /dir1/fileA
:
/dir1/fileC
/dir2/fileB
/dir3/fileD
In my case the lower dir is a periodically synchronized "cold set", a subset of the data is in the upper dir's "hot set". The problem is that if I delete a file from the upperdir, its still present if it was in the lower dir, so deletions require a sync and remount to "take".
Since the upper dir's folders completely alias the lower dir, I would be happy if overlay merges were "shallow", that is, if a directory exists on the upperdir, only its files are present.