Re: tlug: mounting removeable media

[Rex Walters <rex@example.com>]

On Wed, Aug 12, 1998 at 06:32:47PM +0900, Christopher Sekiya wrote:
> 
> On Tue, 11 Aug 1998, Scott Stone wrote:
> 
> > You can use amd to automount local filesystems, but it's considerably more
> > trouble than it's worth.  I've tried it.
> 
> Scott, Scott ... amd was superceded by autofs over a year ago.  Pick up
> the source on ftp.kernel.org

Maybe "obviated" would be a better choice than "superceded".

Amd, for it's sins, is available on more platforms.  If you need to
admin a heterogeneous network (i.e. if you're misfortunate enough to have
"other" unix platforms) amd can be your friend.

The biggest problem with amd (and Sun's original automounter) is the
inability to do directory lookups on an automount point (explicit design
decision: would have to actually mount everything to stat() the contents
-- s-l-o-w).  

amd and automount simply return nothing rather than actually mounting
everything (leading directly to countless luser trouble tickets of the
"MY HOME DIRECTORY IS GONE!" ilk).  That is, amd and automount wait until
you reference an automounted subdirectory explicitly: 

    ls -l /home/user1

returns everything you would expect, while

    ls -l /home

will only show subdirectories that have recently been accessed rather
then all possible automount directories.

It's kind of like 0111 permissions on a normal directory -- you can get
at anything you want IFF you know what it's called.

The Solaris automount developer once talked about making
the automounter simply lie -- e.g. making an "ls -l" in /home return
something like:

    ----------   1 nobody      0           0 Jan  1  1970 user1
    ----------   1 nobody      0           0 Jan  1  1970 user2
    ----------   1 nobody      0           0 Jan  1  1970 usern

Don't know if they ever actually did it though.  

I haven't played with autofs yet.  What does it do if, say, you are
automounting umpteen NFS (or iso9660, VFAT, whatever) filesystems under
/home and you do an "ls -l /home"?

Regards,
-- 
Rex
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