Hey,
I would do:
buy additional HW - I'm personally using small LaCie drive. It's connected via TB (Thunderbolt) and contains 2x1T rotate drive. Easy setup - I am using Raid0 (it means both HDDs from that external device are interlaced - thus faster data). Please read more about it http://en.wikipedia.org/wiki/Standard_RAID_levels it will help you to better understand problematics of raids - nice pics are included!
So in R0 you'll get faster drive, BUT once one of the disk fails - you'll loose all data on that raid. So, I am working on the fast external drive & backup is going to separate drive! Once I'll loose either external or internal drive - I can (and I will) immediately copy data somewhere else (in order to have again 2 copies).
Another benefit you can replace these drives for much faster in future (today the ultimate solution are SSD drives - you can even buy them now https://www.lacie.com/intl/products/product.htm?id=10621 - but it's a bit pricy - at least for me).
I gave up on USB, as I bought it some years ago when there were no solution for 2 HDDs in one usb box (I'm speeaking about 2,5" drives as the 3,5" size is waste of money & most importantly - physical space!! - also energy, etc...). Also USB is VERY slow and no guys - not even 3.1 USB can beat TB2 or even TB3 😉
Of course there are much sophisticated solutions like connecting block device ( iSCSI, FC ), but it cost much more (licenses, HW itself) and I feel here that it would be waste of resources.
For using other MACs for raid - I wouldn't do that - ok, lemme explain what I have in my mind:
- I'd use Raid on each separately - as one unit (one drive export to somewhere else).
- I wouldn't use them as ANY members in one raid (not even 1, 5, 6, 10... doesn't matter) - the network there will simply have wery hight latency & besides the chance of data loss is quite high. Also other aspect as electricity (also for cooling), noise, etc...
- I'd use them as backup for my work.
So I hope now you'll have at least better picture for your solution, even if you'll use some other than I proposed 🙂
P.
