In my 6 x HDD RAIDZ2 pool I have two drives still from its inception around 2017, The other four have been replaced. After coming back from a two-week vacation when my TrueNAS was shut down, I discovered really weird SMART values for these two drives. Basically the 66k+ lifetime hours have suddenly reset and SMART is now counting lifetime from 0 again. Please see the report below, the section reporting the tests that have run.
Have you ever seen such a thing? Happened for both drives at the same time. (Before turning on the server again after the vacation, I did remove a drive that had previously been burnt in, so adaX assignments may have shifted. But SMART data is stored on the drive so I don’t see why that should have mattered.)
Could this be a “65,536 cutoff”? SMART not being capable of counting higher?
smartctl 7.2 2021-09-14 r5236 [FreeBSD 13.1-RELEASE-p9 amd64] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family: Western Digital Red
Device Model: WDC WD40EFRX-68N32N0
Serial Number: WD-WCC7K6RJXHK8
LU WWN Device Id: 5 0014ee 2b9e3a9f5
Firmware Version: 82.00A82
User Capacity: 4,000,787,030,016 bytes [4.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 5400 rpm
Form Factor: 3.5 inches
Device is: In smartctl database [for details use: -P show]
ATA Version is: ACS-3 T13/2161-D revision 5
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Mon Feb 9 06:45:02 2026 CET
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: (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection: Disabled.
Self-test execution status: ( 241) Self-test routine in progress...
10% of test remaining.
Total time to complete Offline
data collection: (45000) 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: ( 478) minutes.
Conveyance self-test routine
recommended polling time: ( 5) minutes.
SCT capabilities: (0x303d) SCT Status supported.
SCT Error Recovery Control 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 157 155 021 Pre-fail Always - 7141
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 125
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 010 010 000 Old_age Always - 66134
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 - 125
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 21
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 239
194 Temperature_Celsius 0x0022 110 101 000 Old_age Always - 40
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
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 200 200 000 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 Extended offline Completed without error 00% 228 -
# 2 Short offline Completed without error 00% 145 -
# 3 Short offline Completed without error 00% 65441 -
# 4 Extended offline Completed without error 00% 65356 -
# 5 Short offline Completed without error 00% 65274 -
# 6 Short offline Completed without error 00% 65105 -
# 7 Extended offline Completed without error 00% 65022 -
# 8 Short offline Completed without error 00% 64938 -
# 9 Extended offline Completed without error 00% 64799 -
#10 Short offline Completed without error 00% 64723 -
#11 Extended offline Aborted by host 10% 64685 -
#12 Short offline Completed without error 00% 64640 -
#13 Extended offline Completed without error 00% 62839 -
#14 Short offline Completed without error 00% 62788 -
#15 Extended offline Completed without error 00% 62543 -
#16 Short offline Completed without error 00% 62020 -
#17 Short offline Completed without error 00% 61777 -
#18 Extended offline Completed without error 00% 61702 -
#19 Short offline Completed without error 00% 61607 -
#20 Short offline Completed without error 00% 61449 -
#21 Extended offline Completed without error 00% 61354 -
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.