I have two directories (a and b), which are NFS shares with files foo.txt and bar.txt:
I want merge this two directories to directory merge (does not have to be writable)
this is possible by command:
sudo mount -t overlay -olowerdir=a:b overlay merge
At first sight everything is ok:
. ├── a │ └── foo.txt ├── b │ └── bar.txt └── merge ├── bar.txt └── foo.txt
But i can not read content of files:
$ cat merge/foo.txt
cat: merge/foo.txt: No such device or address
This occurs only on NFS share, on plain FS no problem.
According to documentation https://www.kernel.org/doc/Documentation/filesystems/overlayfs.txt:
An overlay filesystem combines two filesystems - an 'upper' filesystem and a 'lower' filesystem.
A read-only overlay of two read-only filesystems may use any filesystem type.
So I guess NFS is not a problem.