Raid1 post installation

[Chris Snook]

tony.chamberlain at lemko.com wrote:
> 
> Hello
> 
> They sent off a linux machine (installed with some software) to a customer.
> Normally, when we install Linux (Cent OS 4.5) we do software Raid Level 
> 1 during the
> installation (/dev/sda and /dev/sdb).  This machine went out without 
> them doing it.
> 
> The machine that went out should already  a /dev/sda and /dev/sdb 
> (anyway to verify, if
> /dev/sdb is not mounted?) and we need to perform Raid 1 on it, but we 
> can't reinstall
> Linux on it because it will overwrite evrything that is there.
> 
> Is there anyway to Raid a machine that already has linux installed on it 
> without reinstalling
> Linux over it?
> 
> Thanks
> 

Yes, but to call it dangerous is an understatement.

http://www.linux-sxs.org/hardware/raid_for_idiots.html