I just bought an Ultra 20 with the plan of installing a pair of ZFS
mirrored disks in addition to the boot (system) disk. But I've just
realized the Ultra 20 has room for only 2 disks in the drive cage. Is
there an internal expansion cage available? Has anyone else solved this
problem another way? This is a very lightweight use, a home file server,
so I don't want to get into any kind of dedicated external hardware. If
I need to duct-tape the additional disk in I will, but would prefer
something cleaner.

Thanks,
Arch Stanton