Re: autofs vs. Sun automount -- new fs proposal

Martin Tessun (martin.tessun@class.de)
Tue, 15 Dec 1998 07:15:58 +0100


> The Solaris automounter allows a "seamless" mount of a local directory
> onto another place on the local filesystem. This is frequently used, for
> example, when a user logs in to the actual fileserver. The home directory
> is usually located at /export/home/joeblow and is automounted to
> /home/joeblow when referenced. This could, of course, be achieved by
> actually NFS mounting from the local server. I'd rather shoot myself
> however (am I sure Solaris doesn't do this? no)

Solaris does achieve 'NFS-mounts from the local Server' via a special
"Filesystem", the so called "Loopback Filesystem (lsof)". If you give me
a few days I can look what the lsof does. I expect, that it does
something like a "redirect" or a "special hard-link" without increasing
the Link-Counter.

So what I think you have to do is to write a new filesystem with a new
mount-command (mount.lsof), so that you can do a mount -F lsof
localhost:/export/home/bla /home/bla.

In my opinion this isn't too easy to handle. By the way: I would never
let inexperienced people work on the Fileserver; even I wouldn't let any
person except Administrators work on the fileserver.

> autofs can do this. However, it does so trivially by creating a
> symbolic link which is then traversed. This has mostly cosmetic
> disadvantages, but a few more substatial ones. Any subprocess will see
> the actual 'pwd' of /export/home/joeblow. Thus inexperienced users will
> get confused and bother their system administrator, and, more seriously,
> an application may wrongly determine the location of its private files,
> defeating the 'logical structure' of the filesystem, and preventing
> restructuring of the physical layout.

Martin

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