Hello T,

I have successfully used a utility called Raider a couple of times:  
http://raider.sourceforge.net/  It is proof that what you want to do can 
be done.  Read the README, which is not terribly long.  I don't remember 
the details of the systems used it on, but I recall being impressed at 
the details it handled.  Everything it does can be done by hand with 
various core utilities (which is what raider uses anyway) and it isn't 
terribly hard to understand, but Raider handles a lot of the details 
automatically, making the process less error-prone than trying to go 
through everything by hand.

While it is possible to use Raider on a live, fully functioning system 
to minimize downtime (other than a necessary reboot), you can and often 
should run Raider in single-user mode.  There is a power down to 
physically swap disks and boot from the new degraded array(s), after 
which the new RAID array(s) begin syncing.

Of course, it is strongly recommended that you first clone the disk (or 
at least make a remote backup of any important files) with a utility you 
trust and are familiar with.  (I often use Clonezilla, but there are a 
lot of options for this.)

-Wayne


On 8/18/2017 1:46 PM, ToddAndMargo wrote:
> Hi All,
>
> Is there a way to create software raid 1 after the fact?
> Meaning, you already installed SL on a stand alone drive.
>
> -T