Update, 23 later: the drive failed, most data can't be read, even though the SMART values did not deteriorate a lot. I wanted to replace it in two weeks, since I was busy. Don't fall into a "this won’t happen to me" mindset like I did. Listen to good advice and make a backup ASAP!
I am using a USB HDD (WD Elements 5TB) as a fairly non-critical NAS. Two months ago, I started monitoring SMART values, and they look concerning.
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
March 9
5 Reallocated_Sector_Ct 0x0033 179 179 140 Pre-fail Always - 19848
May 19
5 Reallocated_Sector_Ct 0x0033 177 177 140 Pre-fail Always - 21144
Here is why I am confused:
- The RAW_VALUE indicates that over 20 thousand reallocations have occurred, which seems implausible (?). Similar reports I have read reported obvious issues, but the drive performs fine, and there have not been any filesystem inconsistencies.
- The VALUE/WORST/THRESH are normalized values. To my knowledge, the drive starts at 180, and assumes (imminent) failure as soon as 140 is reached. ATM, 177 is reported.
A decline of 2 points (179 to 177) seems high over ~10 weeks, but seems to imply that the drive still has a large amount of unused reserve sectors, and considers itself to be in decent shape.
No other metrics seem to imply imminent failure or read errors. Western Digitals own software and short self test reported no issues. Could anyone shed some light as to whether this value is actually correct and/or concerning?
Here is a full output of the SMART values.
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 - 27
3 Spin_Up_Time 0x0027 253 253 021 Pre-fail Always - 4200
4 Start_Stop_Count 0x0032 095 095 000 Old_age Always - 5352
5 Reallocated_Sector_Ct 0x0033 177 177 140 Pre-fail Always - 21144
7 Seek_Error_Rate 0x002e 200 193 000 Old_age Always - 0
9 Power_On_Hours 0x0032 084 084 000 Old_age Always - 12145
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 - 436
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 355
193 Load_Cycle_Count 0x0032 189 189 000 Old_age Always - 34277
194 Temperature_Celsius 0x0022 100 091 000 Old_age Always - 52
196 Reallocated_Event_Count 0x0032 001 001 000 Old_age Always - 2346
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 100 253 000 Old_age Offline - 0
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 Short offline Completed without error 00% 10552 -
# 2 Extended offline Aborted by host 90% 10552 -
Selective Self-tests/Logging not supported