Critical SMART errors - Help?

TrueNAS General
1

Hi, long time NAS user, first time forum poster.

I’ve just noticed some critical notifications, and it appears one of my disks is failing SMART tests.

CRITICAL
Device: /dev/ada0, 16 Currently unreadable (pending) sectors.
2026-02-16 00:55:19 (Australia/Brisbane)

CRITICAL
Device: /dev/ada0, Self-Test Log error count increased from 0 to 1.
2026-02-16 00:55:20 (Australia/Brisbane)

I found a post on the old forum suggesting I run smartctl -a /dev/ada0 - the results are below:

=== START OF INFORMATION SECTION ===
Device Model: WDC WD161KFGX-68AFPN0
Serial Number: XXXXXXXX
LU WWN Device Id: X XXXXX XXXXXXXXX
Firmware Version: 83.00A83
User Capacity: 16,000,900,661,248 bytes [16.0 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 7200 rpm
Form Factor: 3.5 inches
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: ACS-4 published, ANSI INCITS 529-2018
SATA Version is: SATA 3.3, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Wed Feb 18 15:54:42 2026 AEST
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: (0x82) Offline data collection activity
was completed without error.
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: ( 101) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No 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: (1708) minutes.
SCT capabilities: (0x003d) 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 0x000b 100 100 001 Pre-fail Always - 0
2 Throughput_Performance 0x0004 137 137 054 Old_age Offline - 92
3 Spin_Up_Time 0x0007 082 082 001 Pre-fail Always - 358 (Average 358)
4 Start_Stop_Count 0x0012 100 100 000 Old_age Always - 33
5 Reallocated_Sector_Ct 0x0033 100 100 001 Pre-fail Always - 0
7 Seek_Error_Rate 0x000a 100 100 001 Old_age Always - 0
8 Seek_Time_Performance 0x0004 128 128 020 Old_age Offline - 18
9 Power_On_Hours 0x0012 096 096 000 Old_age Always - 29883
10 Spin_Retry_Count 0x0012 100 100 001 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 33
22 Unknown_Attribute 0x0023 100 100 025 Pre-fail Always - 100
192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 1272
193 Load_Cycle_Count 0x0012 100 100 000 Old_age Always - 1272
194 Temperature_Celsius 0x0002 040 040 000 Old_age Always - 51 (Min/Max 15/59)
196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 0
197 Current_Pending_Sector 0x0022 100 100 000 Old_age Always - 16
198 Offline_Uncorrectable 0x0008 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x000a 100 100 000 Old_age Always - 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: read failure 90% 29867 -

2 Short offline Completed: read failure 90% 29843 -

3 Short offline Completed: read failure 50% 29819 -

4 Short offline Completed without error 00% 29795 -

5 Short offline Completed without error 00% 29771 -

6 Short offline Completed without error 00% 29747 -

7 Short offline Completed without error 00% 29723 -

8 Short offline Completed without error 00% 29699 -

9 Short offline Completed without error 00% 29675 -

#10 Short offline Completed without error 00% 29651 -
#11 Short offline Completed without error 00% 29627 -
#12 Short offline Completed without error 00% 29603 -
#13 Short offline Completed without error 00% 29579 -
#14 Short offline Completed without error 00% 29555 -
#15 Short offline Completed without error 00% 29531 -
#16 Short offline Completed without error 00% 29507 -
#17 Short offline Completed without error 00% 29483 -
#18 Short offline Completed without error 00% 29460 -
#19 Short offline Completed without error 00% 29435 -
#20 Short offline Completed without error 00% 29411 -
#21 Short offline Completed without error 00% 29387 -

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 disks.
If Selective self-test is pending on power-up, resume after 0 minute delay.

My typical method for monitoring drives is to keep CrystalDiskInfo open in the tray, and take action when Good turns to Bad. I’ve never been able to make sense of all the other information. Is anyone able to take a look at the above readout and let me know how to proceed? Keep an eye on it? Change it out now? Point of no return already passed, succumb to the darkness? All or none of the above?

I haven’t noticed any issues myself accessing the drive, but I’ve had my fair share of hardware failure over the years and know that means absolutely nothing.

2

Full details on your pool could help. Please post data back using Preformatted Text mode (</>) or Ctrl+e. It makes this more readable, like your smart results. One item is the drive reporting 51 C for temp. It’s a bit hot. Check your system cooling. I would make sure you have a good backup of all your data as the drive could fail.
This should tell us your pool setup and it’s current status.
sudo zpool status -v

1 Like
3

Some pending sectors would normally be ok to monitor & plan for a replacement, however, outright smart test failure is something that manufacturer generally rma without push back.

Temps aren’t great & better cooling as barkey mentioned should be considered in the future.

I’d argue it is time for a replacement drive. These are not “loose connection” errors, this is drive itself.

Also consider occasionally having smart long tests in the future, not just shorts.

1 Like
4 
  pool: boot-pool
 state: ONLINE
  scan: scrub repaired 0B in 00:00:01 with 0 errors on Sat Feb 14 03:45:01 2026
config:

        NAME        STATE     READ WRITE CKSUM
        boot-pool   ONLINE       0     0     0
          nvd0p2    ONLINE       0     0     0

errors: No known data errors

  pool: plexdatastore
 state: ONLINE
  scan: scrub repaired 0B in 1 days 13:56:03 with 0 errors on Mon Jan 26 13:56:03 2026
config:

        NAME                                          STATE     READ WRITE CKSUM
        plexdatastore                                 ONLINE       0     0     0
          gptid/c300c106-35b1-11ed-ab10-d8bbc18dd593  ONLINE       0     0     0
          gptid/ebd35221-776d-11ed-8a66-d8bbc18dd593  ONLINE       0     0     0

errors: No known data errors

Preformatted Text Mode is exactly what I was looking for, but didn’t know how to find it.

I wish it was cooler than it was in Australia, unfortunately that’s the best I can manage during the summer days.

5

Long tests are scheduled for the first day of every month. I’m unsure why they aren’t showing up. Quite possibly configured it wrong, but haven’t checked it over in a while.

Looking into RMA procedure (which is already fun, as it was purchased on Amazon.com.au but sold and shipped by Amazon US, so the drive is “out of region”). As someone who hasn’t RMA’d storage before, I assume I need to provide them the defective unit before they provide reimbursement or replacement? So I would have to figure out a temporary storage solution during the RMA process?

6

Your Plexdatastore pool appears to be a two wide stripe configuration. If you lose a single drive, the whole pool is done for. Do you have a backup of the data elsewhere or is it easily replaceable? If both drives are the same size and your pool is at 40% or less capacity, we might be able to remove the ‘bad’ drive from your pool and allow you to RMA it.

7

It is striped across 2 x 16TB WD RED HDDs. It is not backed up, and would be annoying to recover, but is not irreplaceable. I can probably easily enough temporarily relocate some data until the pool is at >40% capacity. I will look into this, and as mentioned above, am looking into the RMA procedure.

8

Is this any official documentation regarding removing a disk from a pool? I can only find forum posts.

9

You might have to change the version of TrueNAS on the docs. It shows replacement.

To Remove a disk from a stripe or mirror VDEV. (screenshots from a VM of TrueNAS 25.10)
Storage, View VDEV, select the disk, click Remove and confirm.
TrueNAS should move the data off the disk you are removing and onto the remaining disk.

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image1561×878 28.5 KB

10

Sometimes they provide an adavnced rma where you pay a deposit & vendor ships asap, then after your drive is received your deposit is refunded. Sometimes you have to ask for that option because they didn’t think of offering it.

But yeah, out of region will be rough.

1 Like
11

Hum, I didn’t know you could remove a stripe drive, learn something new everyday. I didn’t see that in the linked page other than When a disk fails in a Stripe (RAID0) pool, you must recreate the entire pool and restore all data backups.

But maybe it will remove a drive from a stripe without any issues.

My preference would be to “Replace” the drive. Purchase a new 16TB drive, add the drive into your computer and cable it up (do not disconnect your failing drive yet), power on, then in TrueNAS use the Replace function. You will not need to move data off the system, the data will be copied to the new drive. Once all is done, the old drive will be offlined and you can power down and remove the failed drive, then RMA it if it is under warranty.

When you have failures like this, you start to learn that it might be important to add some redundancy.