Read only access to ALL files? Or: how do I safely backup the complete system to an offsite machine?

[Ruben de Groot]

On Fri, Oct 29, 2004 at 02:23:56PM +0200, Gabriel Ambuehl typed:
> Hi,
> I'm wondering if there is any way to have read only access to the whole
> system for an user on STABLE (I have some ideas how to achieve it on
> CURRENT but I don't consider that ready for production use just now)?
> 
> Specifically, I want to be able to ssh in from the backup server and
> fetch all files with rsync without having to give the backup server
> full root access to all other machines (for obvious reasons).
> 
> There's obviously a hack involving NFS and read only/maproot=root
> but seeing that the backup server is offsite, I have to use ssh for
> transport and would rather not resort to VPN hackery...
> 
> Or maybe someone knows of a rsync version that is safe to be run a
> suid root as it won't ever change anything on the filesystem?

Users in the group "operators" have read-only access to the raw 
disk-devices in /dev. These devices are used by dump(8).

All other backup strategies (tar, cpio, rsync, ..) work on the 
filesystem itself rather than the underlying device and will need
root access.

Ruben