I put it in the background and couldn't tell when it ended so instead I opened two ssh connections and ran the two commands at the same time in the separate windows. The output from the second window exceeded the character limit here so there is a link to pastebin.
Code:
root@freenas:~ # dd if=/mnt/Storage/Data/test.dd of=/dev/null
2048000+0 records in
2048000+0 records out
1048576000 bytes transferred in 71.293265 secs (14707925 bytes/sec)