Why not go RAID 10 (1+0) then eliminate the smaller drives after making sure all is on the larger (sort of a double-redundancy)?
You may find you want to keep it in 1+0!
I have a CentOS 5 based Linux system with a 3Ware 9550SU RAID card and four 500GB drives set up in a RAID5 array.
I want to 'replace' these drives with four 2TB drives without data loss. My server case has a total of 8 drive bays all hot-swap and all attached to the RAID card, this means I have four empty drive bays on the RAID card.
One thought is to put the four new 2TB drives in the empty drive bays, configure them in a new RAID5 array. Then the question is now to I "mirror" the original RAID5 array over to the new one?
This is just a thought though, I am not sure it will work. In short my question to this forum is how do I accomplish this upgrade?