How to test OWC Mercury Elite Pro enclosures on FW800?

I bought two OWC Mercury Elite Pro enclosures to build a NAS with a Mac mini (mid-2011), connecting with daisy chained FW800 to make a RAID1 (mirrored). I've installed Debian linux on the Mini currently and I'm having all kinds of weird problems. How can I test the drives to rule in/out a hardware problem, given that they don't have SMART?