OK, but now at least it's throwing an error that makes sense, strange it didn't show the same in the pool, it's not normal:
Aug 23 19:02:32 DataStriver kernel: BTRFS error (device sdd1): devid 2 uuid 4b126ecf-990b-43f5-a5fd-1f31a15ab285 is missing
Since the other device is out of sync, try this:
mkdir /x
mount -o degraded,ro /dev/sdd1 /x
If it doesn't mount post the output, if it does you can browse /x to backup the contents.