Re: replacing /usr with a new mountpoint

[John L Fjellstad <john-debian@fjellstad.org>]

Andrew Sackville-West <andrew@farwestbilliards.com> writes:

> my reading of man mount suggests that you want
>
> mount --rbind / /mnt
> -------^^^
>
> but its not very clearly written (IMO) so I suggest you 
> touch a dummy file in the new /usr and double check whether its in
> /mnt/usr as a test to confirm that the mount of new /usr doesn't carry
> over. 


I'm not sure that's right.

  Since Linux 2.4.0 it is possible to remount part of the file  hierarchy
  somewhere else. The call is
       mount --bind olddir newdir
  After this call the same contents is accessible in two places.  One can
  also remount a single file (on a single file).

  This call attaches only (part of) a  single  filesystem,  not  possible
  submounts.  The entire file hierarchy including submounts is attached a
  second place using
       mount --rbind olddir newdir

This means that if you have something like this
/dev/sda1  /
/dev/sda5  /usr

Doing a --bind on / will only mount /, not /usr, while --rbind will
mount both / and /usr.

According to the original message, he has the original /usr directory 
shadowed by another /usr partition, and what he wants is to remove the
original /usr directory. 

At least that's my understanding.

-- 
John L. Fjellstad
web: http://www.fjellstad.org/          Quis custodiet ipsos custodes