The 0834 line are Fibre Channel disk shelves (ie, they just hold a bunch of disks and aggregate their host interfaces). They take fibre channel disks, not SATA or SAS, and provide a FC interface to one or more host systems (initiators in storage parlance).
Since they're just passing access through they'll support any disk that supports the same physical interface as it provides (eg, if it has 4Gb FC interfaces the disk just has to support the same - most FC devices are backward compatible with a few previous generations of FC).
These systems to not appear to provide hardware RAID capabilities. You would have to find a FC Raid card (I've never seen such an item, but all the requisite technologies exist) or SAN system. Or you could use software RAID.
When you place a larger disk in a RAID than the failed disk it's replacing the extra space is almost always simply wasted. All good RAID systems waste some disk space (a small percentage) to account for variance in capacity between vendors. Playing mix-n-match with disk models, between or within vendors may lead to degraded performance.