Is my FreeNas Raid about to fail?

=== START OF INFORMATION SECTION ===
Model Family: Western Digital Caviar Green (Adv. Format) family
Device Model: WDC WD20EARS-00MVWB0
Serial Number: WD-WMAZA1812508
Firmware Version: 51.0AB51
User Capacity: 2,000,398,934,016 bytes
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Wed Jan 23 14:00:01 2013 GMT
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: ( 0) The previous self-test routine completed
without error or no self-test has ever
been run.
Total time to complete Offline
data collection: (35880) 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: ( 255) 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 200 200 051 Pre-fail Always - 0
3 Spin_Up_Time 0x0027 253 253 021 Pre-fail Always - 1158
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 299
5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0
9 Power_On_Hours 0x0032 092 092 000 Old_age Always - 6370
10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 297
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 296
193 Load_Cycle_Count 0x0032 185 185 000 Old_age Always - 47553
194 Temperature_Celsius 0x0022 111 094 000 Old_age Always - 39
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 126
198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 92
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 200 199 000 Old_age Offline - 207

SMART Error Log Version: 1
ATA Error Count: 93 (device log contains only the most recent five errors)
CR = Command Register [HEX]
FR = Features Register [HEX]
SC = Sector Count Register [HEX]
SN = Sector Number Register [HEX]
CL = Cylinder Low Register [HEX]
CH = Cylinder High Register [HEX]
DH = Device/Head Register [HEX]
DC = Device Command Register [HEX]
ER = Error register [HEX]
ST = Status register [HEX]
Powered_Up_Time is measured from power on, and printed as
DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes,
SS=sec, and sss=millisec. It “wraps” after 49.710 days.

Error 93 occurred at disk power-on lifetime: 5819 hours (242 days + 11 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH


40 51 80 c8 00 00 e0 Error: UNC 128 sectors at LBA = 0x000000c8 = 200

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name


c8 00 80 80 00 00 e0 00 00:04:04.783 READ DMA
c8 00 80 00 00 00 e0 00 00:04:04.783 READ DMA
b0 d0 01 00 4f c2 e0 00 00:04:04.777 SMART READ DATA
b0 da 00 00 4f c2 e0 00 00:04:04.694 SMART RETURN STATUS
c8 00 80 80 00 00 e0 00 00:04:02.038 READ DMA

Error 92 occurred at disk power-on lifetime: 5819 hours (242 days + 11 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH


40 51 80 d0 00 00 e0 Error: UNC 128 sectors at LBA = 0x000000d0 = 208

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name


c8 00 80 80 00 00 e0 00 00:04:02.038 READ DMA
c8 00 80 00 00 00 e0 00 00:04:02.035 READ DMA
b0 d5 01 01 4f c2 e0 00 00:04:02.033 SMART READ LOG
c8 00 80 80 00 00 e0 00 00:03:59.377 READ DMA
c8 00 80 00 00 00 e0 00 00:03:59.374 READ DMA

Error 91 occurred at disk power-on lifetime: 5819 hours (242 days + 11 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH


40 51 80 d0 00 00 e0 Error: UNC 128 sectors at LBA = 0x000000d0 = 208

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name


c8 00 80 80 00 00 e0 00 00:03:59.377 READ DMA
c8 00 80 00 00 00 e0 00 00:03:59.374 READ DMA
b0 d5 01 06 4f c2 e0 00 00:03:59.373 SMART READ LOG
c8 00 80 80 00 00 e0 00 00:03:56.717 READ DMA
c8 00 80 00 00 00 e0 00 00:03:56.717 READ DMA

Error 90 occurred at disk power-on lifetime: 5819 hours (242 days + 11 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH


40 51 80 c8 00 00 e0 Error: UNC 128 sectors at LBA = 0x000000c8 = 200

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name


c8 00 80 80 00 00 e0 00 00:03:56.717 READ DMA
c8 00 80 00 00 00 e0 00 00:03:56.717 READ DMA
b0 d1 01 01 4f c2 e0 00 00:03:56.711 SMART READ ATTRIBUTE THRESHOLDS [OBS-4]
c8 00 80 80 00 00 e0 00 00:03:54.056 READ DMA
c8 00 80 00 00 00 e0 00 00:03:54.056 READ DMA

Error 89 occurred at disk power-on lifetime: 5819 hours (242 days + 11 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH


40 51 80 c8 00 00 e0 Error: UNC 128 sectors at LBA = 0x000000c8 = 200

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name


c8 00 80 80 00 00 e0 00 00:03:54.056 READ DMA
c8 00 80 00 00 00 e0 00 00:03:54.056 READ DMA
b0 d0 01 00 4f c2 e0 00 00:03:54.049 SMART READ DATA
c8 00 80 80 00 00 e0 00 00:03:51.186 READ DMA
c8 00 80 00 00 00 e0 00 00:03:51.186 READ DMA

SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error

1 Conveyance offline Completed without error 00% 70 -

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.

S.M.A.R.T. [/dev/ad10]:

smartctl 5.40 2010-10-16 r3189 [FreeBSD 7.3-RELEASE-p3 amd64] (local build)
Copyright © 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net

I’d be concerned about the following attributes:

197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 126
198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 92

The UNCorrectable errors at LBA = 0x000000c8 are near the beginning of the drive. That could be where the server OS or important file system structures live.