overlay filesystem help needed

igadoter · 07-03-2021, 10:49 AM

I just found about overlay file system. I mean it file system created from two other file systems. But I still don't get it how it works. It will we be good to have such thing. Can I use nfs as one of layers? It is really great things as directory are merged.

berndbausch · 07-03-2021, 08:56 PM

From the kernel documentation (emphasis mine):

Quote:

The lower filesystem can be any filesystem supported by Linux and does
not need to be writable. The lower filesystem can even be another
overlayfs. The upper filesystem will normally be writable and if it
is it must support the creation of trusted.* extended attributes, and
must provide valid d_type in readdir responses, so NFS is not suitable.

A read-only overlay of two read-only filesystems may use any
filesystem type.