Miklos Szeredi:

Aufs provides much better filesystem semantics than either unionmounts
or overlayfs.  But that does come at a price:

aufs:       98 files changed, 29893 insertions(+), 7 deletions(-)
overlayfs:  22 files changed, 2981 insertions(+), 10 deletions(-)

Yes, I have to admit that aufs grew up very big.
The fundamental (by design) difference between them is considering how
important the filesystem semantics is. You may dislike a big module,
but I am interested in how you (or someone else) will implement the
missing overlayfs features to keep the semantics. One approach is
implemented in aufs. I guess you will try another one. That is what I am
interesed.


J. R. Okajima