Re: Union file system

Mailing List Receiver (
Wed, 27 Nov 1996 11:44:58 -0500 (EST)

On Wed, 27 Nov 1996, D. Chiodo wrote:

> > Does anybody know of a union file system for Linux? Alternatively any
> > writeups on why it is/is not a good idea?
> Symlinks? Mount all the cd, network, disk, etc, then make symlinks from
> whereyou want you everything to appear to wherever the appropriate files
> are...

I don't think symlinks cut it for what Mr. Owens is talking about. It
would be difficult to maintain such a huge farm of symlinks; not to
mention that you would have to remove certain symlinks before installing
files to the top level.

Moreover, the symlink approach is short sighted on the whole... if there
were a union file system, I would expect it to do two _or more_ underlying
filesystems.. Imagine a cdrom, plus an nfs-mounted directory, plus a
local hard drive (which would be the top layer). I can see where this
could be helpful. The symlink approach is not sufficient in this case,
because if the files change on the nfs directory, those changes are not
automatically reflected on the union filesystem.

-Tom Kludy