If you still have 3 free disks it's no problem (It's probably best to use RAID 4 + Spare in that case, and remember that the "current" controller still needs at least one spare!)
However, you need a downtime/reboot for this procedure
just do this:
- options disk.auto_assign off (this prevents the current controller from
- priv set diag
- disk remove_ownership <diskid> (for all 3 disks that you have leftover. Make sure that you get the right disks here!)
- license add <licensekey> (you should have received this when you bought the second controller)
- plug in the second controller and do a base setup via serial
- do a reboot of the first controller to enable HA takeover features
- make sure that you set up the partner VIFs correctly from here on (use any NetApp base setup guide as reference)
(mostly the "ifconfig" lines in /etc/rc need a "partner" definition, you need to do "cf enable", and test takeover/giveback)
-Michael