[lug] Live disk attach?

[William Petty]

Two Questions.
1) I am trying to do some hard drive debugging on a live running Linux 
system.  I am
attaching an unknown drive to the second channel of my SCSI controller and 
powering
it up.  It there a way for the OS to re-scan for the new device without 
rebooting?
My intention is to run fdisk and mkfs and perform various integrity checks 
on many
different drives without rebooting each time.

2) When doing full backups, what is the best method (using a commonly bundled
program), and what should be in the backup file set?  When I was on DOS or OS2,
I used to just backup C: and or D: with tar.  What was great, was that I 
was able to
replace the hard drive, boot a minimal floppy based system and restore all.
Upon reboot, it was as if nothing had changed except having new drive. 
(Usually bigger)

Can this be done for Linux?  I.E. boot of a CD and restore all from tape.