[lug] Raid question

[Carl Wagner]

Hi,

I have a Debian box using software RAID on 2 drives (mirroring). 
One of the drives was failing so I removed it (it was causing a lot of 
strange issues).
I have done a few upgrades on this box and rebooted it after each of 
them to make sure they did not break anything.  This is with the bad 
drive missing.

I pulled a spare drive out of another system that is about the same size.
How do I get the mirroring working again and make sure I don't scramble 
the good drive?
Will a simple boot work and somehow detect which drive is the raid drive. 

The other drive was pulled from a working system.
Should I format the "new" drive just to make sure it does not become the 
master?

After booting, will I need to do:
  

mdadm /dev/md0 -a /dev/sda1
...

To all the partitions?

Thanks,
Carl.