I'm thinking of building a new PC later this year that will include a RAID 1 based on 600 GB WD VelociRaptors. I'll further back this up by copying images of the RAID to a pair of external drives rotated offsite (i.e., one drive will always be onsite, the other offsite). In principle, I don't care much about the performance of the external drives, but it occurs to me that if I make them identical to the ones in the RAID then, in the off-chance I actually experience a failure in the RAID, I can just remove the onsite external drive from its case, swap it in, and be back exactly where I started (after the RAID rebuilds). Then order the replacement for the external drive.
The VelociRaptors are SATA 3, however, and there are few external SATA 3 enclosures with USB 2.0 interfaces. While I may build the new PC with USB 3.0 or eSATA ports, I'd like to get the drives now and start using them with my current PC to reduce the dollar shock when building the new one; my current PC only has USB 2.0 and Firewire ports. There are loads of SATA 2 external enclosures, though, so I was wondering if I could plug the VelociRaptors into one of these, assuming I don't care about the performance hit, if any (it's not clear to me that the VelociRaptors are capable of saturating even a SATA 2 connection very often)? Thanks.