[root@freenaspol] /# zpool status
  pool: VOLUME1
 state: ONLINE
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://illumos.org/msg/ZFS-8000-8A
  scan: scrub repaired 0 in 5h18m with 55 errors on Sun Sep 20 05:18:43 2015
config:
        NAME                                          STATE     READ WRITE CKSUM
        VOLUME1                                       ONLINE       0     0     0
          gptid/d1801141-f885-11e2-9326-9c8e9908a74c  ONLINE       0     0     0
errors: 3 data errors, use '-v' for a list
  pool: VOLUME2
 state: ONLINE
status: The pool is formatted using a legacy on-disk format.  The pool can
        still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'.  Once this is done, the
        pool will no longer be accessible on software that does not support feature
        flags.
  scan: scrub repaired 0 in 2h13m with 0 errors on Sun Sep 20 02:13:46 2015
config:
        NAME                                          STATE     READ WRITE CKSUM
        VOLUME2                                       ONLINE       0     0     0
          gptid/e4769134-f885-11e2-9326-9c8e9908a74c  ONLINE       0     0     0
errors: No known data errors
  pool: VOLUME3
 state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
        still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(7) for details.
  scan: scrub repaired 0 in 7h11m with 0 errors on Sun Sep  6 07:11:26 2015
config:
        NAME                                          STATE     READ WRITE CKSUM
        VOLUME3                                       ONLINE       0     0     0
          gptid/bc0208bb-29f5-11e3-a7a7-9c8e9908a74c  ONLINE       0     0     0
errors: No known data errors
  pool: freenas-boot
 state: ONLINE
  scan: none requested
config:
        NAME        STATE     READ WRITE CKSUM
        freenas-boot  ONLINE       0     0     0
          ada0p2    ONLINE       0     0     0
errors: No known data errors
[root@freenaspol] /# smartctl -a /dev/ada1
smartctl 6.3 2014-07-26 r3976 [FreeBSD 9.3-RELEASE-p26 amd64] (local build)
Copyright (C) 2002-14, Bruce Allen, Christian Franke, 
www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Caviar Green (AF, SATA 6Gb/s)
Device Model:     WDC WD20EARX-00PASB0
Serial Number:    WD-WCAZAH949508
LU WWN Device Id: 5 0014ee 2b20786b8
Firmware Version: 51.0AB51
User Capacity:    2,000,398,934,016 bytes [2.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Thu Oct  8 14:29:21 2015 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
General SMART Values:
Offline data collection status:  (0x84) Offline data collection activity
                                        was suspended by an interrupting command from host.
                                        Auto Offline Data Collection: Enabled.
Self-test execution status:      ( 121) The previous self-test completed having
                                        the read element of the test failed.
Total time to complete Offline
data collection:                (39900) seconds.
Offline data collection
capabilities:                    (0x7b) SMART execute Offline immediate.
                                        Auto Offline data collection on/off support.
                                        Suspend Offline collection upon new
                                        command.
                                        Offline surface scan supported.
                                        Self-test supported.
                                        Conveyance Self-test supported.
                                        Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                                        power-saving mode.
                                        Supports SMART auto save timer.
Error logging capability:        (0x01) Error logging supported.
                                        General Purpose Logging supported.
Short self-test routine
recommended polling time:        (   2) minutes.
Extended self-test routine
recommended polling time:        ( 384) minutes.
Conveyance self-test routine
recommended polling time:        (   5) minutes.
SCT capabilities:              (0x3035) SCT Status supported.
                                        SCT Feature Control supported.
                                        SCT Data Table supported.
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   199   199   051    Pre-fail  Always       -       9314
  3 Spin_Up_Time            0x0027   186   162   021    Pre-fail  Always       -       5683
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       40
  5 Reallocated_Sector_Ct   0x0033   160   160   140    Pre-fail  Always       -       1695
  7 Seek_Error_Rate         0x002e   200   200   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   067   067   000    Old_age   Always       -       24754
 10 Spin_Retry_Count        0x0032   100   253   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       36
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       18
193 Load_Cycle_Count        0x0032   001   001   000    Old_age   Always       -       1479214
194 Temperature_Celsius     0x0022   123   114   000    Old_age   Always       -       27
196 Reallocated_Event_Count 0x0032   001   001   000    Old_age   Always       -       442
197 Current_Pending_Sector  0x0032   198   195   000    Old_age   Always       -       817
198 Offline_Uncorrectable   0x0030   193   193   000    Old_age   Offline      -       2397
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   148   148   000    Old_age   Offline      -       13955
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed: read failure       90%     24748         676876826
# 2  Extended offline    Completed: read failure       90%     24732         676883541
SMART Selective self-test log data structure revision number 1
 SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
    1        0        0  Not_testing
    2        0        0  Not_testing
    3        0        0  Not_testing
    4        0        0  Not_testing
    5        0        0  Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.