Uh oh...

/sbin/lsraid -a /dev/md0
[dev   9,   0] /dev/md0         CD3295E2.945D4D13.7961C1FF.F79E9355 online
[dev   ?,   ?] (unknown)        00000000.00000000.00000000.00000000 missing
[dev  34,   1] /dev/hdg1        CD3295E2.945D4D13.7961C1FF.F79E9355 good

One of the hard drives on my file server is "missing." Uh oh.