[root@n1] ~# zpool status -v
pool: data
state: DEGRADED
status: One or more devices has experienced an error resulting in data corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the entire pool from backup.
see: http://www.sun.com/msg/ZFS-8000-8A
scrub: none requested
config:NAME STATE READ WRITE CKSUM
data DEGRADED 0 0 18
raidz1 DEGRADED 0 0 50
ada0p2 ONLINE 0 0 4
ada1p2 ONLINE 0 0 0
3024388728382954071 UNAVAIL 0 0 0 was /dev/ada1p2
ada2p2 ONLINE 0 0 0
ada3p2 ONLINE 0 0 0
[root@n1] /data# sqlite3 freenas-v1.db
SQLite version 3.7.9 2011-11-01 00:52:41
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> select * from storage_disk;
1|Disabled|Always On|S24087AK||{serial}S24087AK|1|Disabled|Auto||||2|ada0
1|Disabled|Always On|S24087NL||{serial}S24087NL|1|Disabled|Auto||||4|ada1
1|Disabled|Always On|S2408AAT||{serial}S2408AAT|1|Disabled|Auto||||5|ada2
1|Disabled|Always On|S2408AGL||{serial}S2408AGL|1|Disabled|Auto||||6|ada3
0|Disabled|Always On|||{devicename}da0|1|Disabled|Auto||||7|da0
Then look for the drive that has a serial number that is not listed above.