IDE backup on single host (was: Re: Software backup)

[Jarno Elonen <elonen@iki.fi>]

> We're using rsync to mirror a hot drive in our main server to a cold drive
> (one that is only mounted when backing up, and is briefly mounted read only
> for per file restoration).

...which reminds me of a related problem of mine. On my own system, I'm using 
a fixed spare IDE hard drive for backups. Every night, Backup2l automatically 
mounts it, makes an incremental backup and then unmount it again.

While not a remote backup scheme, this protects the system from most common 
destructive mistakes and malfunctions like "sudo rm -rf * - whoops, What whas 
I thinking?!!" or software that goes wild and does similar things.

But: all the backups can be erased with one simple line:
"dd if=/dev/zero of=/dev/<backup-disk>". :(

Does anyone know any way to make this more difficult without introducing a 
remote host? Are there, for example, any Linux kernel options for "device 
access passwords" or such?

- Jarno