Can't import a pool, but no errors

TrueNAS General
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1

Hi y’all,

I recently had to reinstall TrueNAS due to an issue on my boot device causing a persistent kernel panic. I’ve got that sorted (for now, at least) but I’m running into an issue attempting to import my existing pools. I’ve got two, and one imported no problem, but the other is giving me fits. I attempted to import it via the web GUI, and every time I try that, after about 30 seconds the web interface informs me that my session has expired and prompts me with the login screen. The import dialogue never progresses past 0.00%.

I tried importing via the shell built into the GUI, and encounter the same problem. So I tried via the terminal on my computer, SSH’d into the server, and the same thing happens. If I have the web GUI up when I attempt the import, after about 30 seconds the session expires. The terminal session presumably hangs, because I’ve let it sit for a while (about 30 minutes on my most patient effort) before ctrl+c’ing, at which point it boots me from the SSH session with a broken pipe message. I’ve tried running zpool import [pool name], zpool import -f, zpool import -R /mnt, all commands have the same result. Running just zpool import, with not poolname, does find the importable pool, so it’s out there and it’s identified. It shows as online, which I think is expected pre-import but I’m not 100% on that, and there’s a caveat stating “Some supported features are not enabled on the pool. (Note that they may be intentionally disabled if the ‘compatibility’ property is set.)” I have not attempted a zfs upgrade, my understanding is that that’s a slippery slope, and I don’t think I could upgrade zfs on that pool right now anyway, since it’s yet to be imported.

Thanks for any help!

2

It would be helpful if you listed all your hardware, especially the disk maker, model and how the disks are connected to the system board.

Next, please supply the output of the following in CODE tags:

lsblk -o NAME,MODEL,SERIAL,LABEL,UUID,PARTUUID,TYPE
zpool import

Yes, if the drives are present, they would show ONLINE. The simple listing a pre-import does, won’t show corruption or other issues.

This is common and in general you don’t want to upgrade your pool unless you have a specific need for a feature.

1 Like
3

Hardware I can give a general overview of right now… I’m afraid I don’t know the disk specifics offhand, I’ll have to wait until later when I’m able to go disassemble the tower and check. I know the impacted pool is a pair of mirrored 12TB HDDs. The rest of the system is a Ryzen 5825U CPU, 32GB of DDR4, a 128GB boot NVMe, and mirrored 1TB NVMe SSDs as a second pool. That one imported fine. The HDD pool is connected via SATA to the motherboard, I’m not using a USB enclosure or DAS. Here’s the requested output:

root@truenas[/home/truenas_admin]# lsblk -o NAME,MODEL,SERIAL,LABEL,UUID,PARTUUID,TYPE
NAME MODEL SERIAL LABEL UUID                                 PARTUUID                             TYPE
sda  HUH72 8DJE9R                                                                                 disk
└─sda1
                  bigboi
                        17023558984181591159                 e4dffae7-cd8c-4ee6-803d-9896e06d17d0 part
sdb  HUH72 8DJ4BR                                                                                 disk
└─sdb1
                  bigboi
                        17023558984181591159                 b08aa5f6-1d49-4444-8d04-d1266905a581 part
nvme1n1
     Patri P300ND                                                                                 disk
├─nvme1n1p1
│                                                            a7dcf7c4-e782-49d7-82a7-19d1c1f3ea4a part
├─nvme1n1p2
│                 EFI   EF18-7E54                            ddc0616c-e4d4-41f2-8c71-628989cf2695 part
└─nvme1n1p3
                  boot-pool
                        12551917559314348110                 1b41b507-afe8-4c8a-a083-ffc2119e9219 part
nvme0n1
     CT100 2334E8                                                                                 disk
└─nvme0n1p1
                  fastboi
                        3181439467038916935                  873c69dc-c0dd-4429-ab0d-953472358daf part
root@truenas[/home/truenas_admin]# 

root@truenas[/home/truenas_admin]# zpool import
  pool: bigboi
    id: 17023558984181591159
 state: ONLINE
status: Some supported features are not enabled on the pool.
	(Note that they may be intentionally disabled if the
	'compatibility' property is set.)
action: The pool can be imported using its name or numeric identifier, though
	some features will not be available without an explicit 'zpool upgrade'.
config:

	bigboi                                    ONLINE
	  mirror-0                                ONLINE
	    b08aa5f6-1d49-4444-8d04-d1266905a581  ONLINE
	    e4dffae7-cd8c-4ee6-803d-9896e06d17d0  ONLINE
root@truenas[/home/truenas_admin]#

It’s also worth noting that I’ve made some progress since posting this. The import fails unless I attempt to import the pool as read only, near as I can tell. Here’s what I can accomplish:

root@truenas[/home/truenas_admin]# zpool import -o readonly=on -f bigboi
cannot mount '/bigboi': failed to create mountpoint: Read-only file system
Import was successful, but unable to mount some datasets
root@truenas[/home/truenas_admin]# zpool status
  pool: bigboi
 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: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 6.50M in 19:26:41 with 10 errors on Sun Oct 19 17:26:43 2025
config:

	NAME                                      STATE     READ WRITE CKSUM
	bigboi                                    ONLINE       0     0     0
	  mirror-0                                ONLINE       0     0     0
	    b08aa5f6-1d49-4444-8d04-d1266905a581  ONLINE       0     0     0
	    e4dffae7-cd8c-4ee6-803d-9896e06d17d0  ONLINE       0     0     0

errors: 3433 data errors, use '-v' for a list

  pool: boot-pool
 state: ONLINE
config:

	NAME         STATE     READ WRITE CKSUM
	boot-pool    ONLINE       0     0     0
	  nvme1n1p3  ONLINE       0     0     0

errors: No known data errors

  pool: fastboi
 state: DEGRADED
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: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 0B in 00:04:39 with 0 errors on Sat Oct 18 22:04:41 2025
config:

	NAME                                    STATE     READ WRITE CKSUM
	fastboi                                 DEGRADED     0     0     0
	  873c69dc-c0dd-4429-ab0d-953472358daf  DEGRADED     0     0     0  too many errors

errors: 2 data errors, use '-v' for a list
root@truenas[/home/truenas_admin]# zpool export bigboi
root@truenas[/home/truenas_admin]#

And the pool exports successfully. If I try and import it again after that with the read only property toggled off, it goes right back to failing. And zfs set readonly=off bigboi gives me a message that that property can only be set during import, which I understand is normal.

1 Like
4

TrueNAS wants -R /mnt for mountpoint. So try

zpool import -R /mnt -o readonly=on -f bigboi
zpool status -v

so we see these errors.

5

Gotcha. I’ve redacted quite a bit from the errors, every one of them is data stored on the drives. The import did appear to go more smoothly this time, at least - no message about some datasets not mounting.

Welcome to TrueNAS
Last login: Wed Nov 26 10:48:35 2025 from 192.168.68.56
truenas_admin@truenas[~]$ sudo -s
[sudo] password for truenas_admin: 
root@truenas[/home/truenas_admin]# zpool import -R /mnt -o readonly=on -f bigboi 
root@truenas[/home/truenas_admin]# zpool status -v
  pool: bigboi
 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: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 6.50M in 19:26:41 with 10 errors on Sun Oct 19 17:26:43 2025
config:

	NAME                                      STATE     READ WRITE CKSUM
	bigboi                                    ONLINE       0     0     0
	  mirror-0                                ONLINE       0     0     0
	    b08aa5f6-1d49-4444-8d04-d1266905a581  ONLINE       0     0     0
	    e4dffae7-cd8c-4ee6-803d-9896e06d17d0  ONLINE       0     0     0

errors: Permanent errors have been detected in the following files:

        /mnt/bigboi/[redacted]
        /mnt/bigboi/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Movies/[redacted]
        /mnt/bigboi/Media/TV/[redacted]
        bigboi/Media:<0x8f0f>
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        bigboi/Media:<0x9828>
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Music/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Music/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Music/[redacted]
        /mnt/bigboi/Media/Movies/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        /mnt/bigboi/Media/Downloads/[redacted]
        [a whole bunch more redacted stuff here that's just more of the above]

  pool: boot-pool
 state: ONLINE
config:

	NAME         STATE     READ WRITE CKSUM
	boot-pool    ONLINE       0     0     0
	  nvme1n1p3  ONLINE       0     0     0

errors: No known data errors

  pool: fastboi
 state: DEGRADED
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: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 0B in 00:04:39 with 0 errors on Sat Oct 18 22:04:41 2025
config:

	NAME                                    STATE     READ WRITE CKSUM
	fastboi                                 DEGRADED     0     0     0
	  873c69dc-c0dd-4429-ab0d-953472358daf  DEGRADED     0     0     0  too many errors

errors: Permanent errors have been detected in the following files:

        /mnt/.ix-apps/docker/overlay2/6a064a325809f85332e1991fbd56b29040c8014deaa2aa21a138bf416afa4d83/diff/app/bin/System.Private.CoreLib.dll
root@truenas[/home/truenas_admin]#
6

You also have metadata errors:

bigboi/Media:<0x8f0f>
bigboi/Media:<0x9828>

These might go away by deleting the damaged files. Or not. In the latter case, the only fix is to destroy the pool and restore from backup. If you can only import read-only, this is the way.
And there are also errors in the NVMe pool—most likely fixable by redeploying the container. If it were me, I’d run MemTest and stress test the CPU to make sure it was “just” the boot drive and not something more serious.

1 Like
7

I agree with the below:

Heavy pool corruption usually has some serious hardware fault that caused it. Sometimes fixable to the point of no data lost. (Like bad SATA cable causing data read back, to look corrupt… but really okay.) However, other times the data was written corrupt. Even to both Mirrors…

You might check the SMART output for the 2 x 12TB HDDs:

smartctl -x /dev/sda
smartctl -x /dev/sdb
8

Okay, here’s the output for the smartctl command. It’s pretty lengthy, and I’m not sure what to make of a lot of it.

root@truenas[/home/truenas_admin]# smartctl -x /dev/sda 
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.12.33-production+truenas] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     HUH721212ALE601
Serial Number:    8DJE9RUY
LU WWN Device Id: 5 000cca 253e23c61
Firmware Version: LEGL0002
User Capacity:    12,000,138,625,024 bytes [12.0 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        Not in smartctl database 7.3/5528
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Thu Nov 27 09:26:51 2025 PST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is:   Unavailable
APM feature is:   Disabled
Rd look-ahead is: Enabled
Write cache is:   Enabled
DSN feature is:   Unavailable
ATA Security is:  Disabled, frozen [SEC2], Master PW ID: 0xfffd
Wt Cache Reorder: 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:      (   0)	The previous self-test routine completed
					without error or no self-test has ever 
					been run.
Total time to complete Offline 
data collection: 		(   87) 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: 	 (   1) minutes.
Extended self-test routine
recommended polling time: 	 (   1) 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          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  1 Raw_Read_Error_Rate     PO-R--   100   100   016    -    0
  2 Throughput_Performance  P-S---   130   130   054    -    100
  3 Spin_Up_Time            POS---   165   165   024    -    410 (Average 389)
  4 Start_Stop_Count        -O--C-   100   100   000    -    98
  5 Reallocated_Sector_Ct   PO--CK   100   100   005    -    0
  7 Seek_Error_Rate         PO-R--   100   100   067    -    0
  8 Seek_Time_Performance   P-S---   140   140   020    -    15
  9 Power_On_Hours          -O--C-   094   094   000    -    47673
 10 Spin_Retry_Count        PO--C-   100   100   060    -    0
 12 Power_Cycle_Count       -O--CK   100   100   000    -    59
 22 Unknown_Attribute       PO---K   100   100   025    -    100
 45 Unknown_Attribute       PO---K   100   100   001    -    1095233372415
192 Power-Off_Retract_Count -O--CK   100   100   000    -    1007
193 Load_Cycle_Count        -O--C-   100   100   000    -    1007
194 Temperature_Celsius     -O----   181   181   000    -    33 (Min/Max 20/54)
196 Reallocated_Event_Count -O--CK   100   100   000    -    0
197 Current_Pending_Sector  -O---K   100   100   000    -    0
198 Offline_Uncorrectable   ---R--   100   100   000    -    0
199 UDMA_CRC_Error_Count    -O-R--   200   200   000    -    0
231 Temperature_Celsius     -O--CK   100   100   000    -    0
241 Total_LBAs_Written      -O--C-   100   100   000    -    3588799475544
242 Total_LBAs_Read         -O--C-   100   100   000    -    6130614288834
                            ||||||_ K auto-keep
                            |||||__ C event count
                            ||||___ R error rate
                            |||____ S speed/performance
                            ||_____ O updated online
                            |______ P prefailure warning

General Purpose Log Directory Version 1
SMART           Log Directory Version 1 [multi-sector log support]
Address    Access  R/W   Size  Description
0x00       GPL,SL  R/O      1  Log Directory
0x01           SL  R/O      1  Summary SMART error log
0x02           SL  R/O      1  Comprehensive SMART error log
0x03       GPL     R/O      1  Ext. Comprehensive SMART error log
0x04       GPL     R/O    256  Device Statistics log
0x04       SL      R/O    255  Device Statistics log
0x06           SL  R/O      1  SMART self-test log
0x07       GPL     R/O      1  Extended self-test log
0x08       GPL     R/O      2  Power Conditions log
0x09           SL  R/W      1  Selective self-test log
0x0c       GPL     R/O   5501  Pending Defects log
0x10       GPL     R/O      1  NCQ Command Error log
0x11       GPL     R/O      1  SATA Phy Event Counters log
0x12       GPL     R/O      1  SATA NCQ Non-Data log
0x13       GPL     R/O      1  SATA NCQ Send and Receive log
0x15       GPL     R/W      1  Rebuild Assist log
0x21       GPL     R/O      1  Write stream error log
0x22       GPL     R/O      1  Read stream error log
0x24       GPL     R/O    256  Current Device Internal Status Data log
0x25       GPL     R/O    256  Saved Device Internal Status Data log
0x30       GPL,SL  R/O      9  IDENTIFY DEVICE data log
0x80       GPL     R/W    688  Host vendor specific log
0x81-0x9f  GPL,SL  R/W     16  Host vendor specific log
0xb2       GPL     VS     688  Device vendor specific log
0xc8       GPL     VS      12  Device vendor specific log
0xe0       GPL,SL  R/W      1  SCT Command/Status
0xe1       GPL,SL  R/W      1  SCT Data Transfer

SMART Extended Comprehensive Error Log Version: 1 (1 sectors)
No Errors Logged

SMART Extended Self-test Log Version: 1 (1 sectors)
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed without error       00%     47071         -
# 2  Short offline       Completed without error       00%     47047         -
# 3  Short offline       Completed without error       00%     47023         -
# 4  Short offline       Completed without error       00%     46999         -
# 5  Short offline       Completed without error       00%     46975         -
# 6  Short offline       Completed without error       00%     46951         -
# 7  Short offline       Completed without error       00%     46928         -
# 8  Short offline       Completed without error       00%     46903         -
# 9  Short offline       Completed without error       00%     46879         -
#10  Short offline       Completed without error       00%     46855         -
#11  Short offline       Completed without error       00%     46831         -
#12  Short offline       Completed without error       00%     46807         -
#13  Short offline       Completed without error       00%     46783         -
#14  Short offline       Completed without error       00%     46759         -
#15  Short offline       Completed without error       00%     46735         -
#16  Short offline       Completed without error       00%     46711         -
#17  Short offline       Completed without error       00%     46687         -
#18  Short offline       Completed without error       00%     46663         -
#19  Short offline       Completed without error       00%     46639         -

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.

SCT Status Version:                  3
SCT Version (vendor specific):       256 (0x0100)
Device State:                        Active (0)
Current Temperature:                    33 Celsius
Power Cycle Min/Max Temperature:     32/36 Celsius
Lifetime    Min/Max Temperature:     20/54 Celsius
Under/Over Temperature Limit Count:   0/0

SCT Temperature History Version:     2
Temperature Sampling Period:         1 minute
Temperature Logging Interval:        1 minute
Min/Max recommended Temperature:      0/60 Celsius
Min/Max Temperature Limit:           -40/70 Celsius
Temperature History Size (Index):    128 (27)

Index    Estimated Time   Temperature Celsius
  28    2025-11-27 07:19    33  **************
 ...    ..(126 skipped).    ..  **************
  27    2025-11-27 09:26    33  **************

SCT Error Recovery Control:
           Read: Disabled
          Write: Disabled

Device Statistics (GP Log 0x04)
Page  Offset Size        Value Flags Description
0x01  =====  =               =  ===  == General Statistics (rev 1) ==
0x01  0x008  4              59  ---  Lifetime Power-On Resets
0x01  0x010  4           47673  ---  Power-on Hours
0x01  0x018  6   3588799475544  ---  Logical Sectors Written
0x01  0x020  6      5187538948  ---  Number of Write Commands
0x01  0x028  6   6130614288834  ---  Logical Sectors Read
0x01  0x030  6      9398805693  ---  Number of Read Commands
0x01  0x038  6    171625478450  ---  Date and Time TimeStamp
0x03  =====  =               =  ===  == Rotating Media Statistics (rev 1) ==
0x03  0x008  4           47334  ---  Spindle Motor Power-on Hours
0x03  0x010  4           47334  ---  Head Flying Hours
0x03  0x018  4            1007  ---  Head Load Events
0x03  0x020  4               0  ---  Number of Reallocated Logical Sectors
0x03  0x028  4              63  ---  Read Recovery Attempts
0x03  0x030  4               0  ---  Number of Mechanical Start Failures
0x04  =====  =               =  ===  == General Errors Statistics (rev 1) ==
0x04  0x008  4               0  ---  Number of Reported Uncorrectable Errors
0x04  0x010  4               0  ---  Resets Between Cmd Acceptance and Completion
0x05  =====  =               =  ===  == Temperature Statistics (rev 1) ==
0x05  0x008  1              33  ---  Current Temperature
0x05  0x010  1              32  N--  Average Short Term Temperature
0x05  0x018  1              33  N--  Average Long Term Temperature
0x05  0x020  1              54  ---  Highest Temperature
0x05  0x028  1              20  ---  Lowest Temperature
0x05  0x030  1              53  N--  Highest Average Short Term Temperature
0x05  0x038  1              24  N--  Lowest Average Short Term Temperature
0x05  0x040  1              52  N--  Highest Average Long Term Temperature
0x05  0x048  1              25  N--  Lowest Average Long Term Temperature
0x05  0x050  4               0  ---  Time in Over-Temperature
0x05  0x058  1              60  ---  Specified Maximum Operating Temperature
0x05  0x060  4               0  ---  Time in Under-Temperature
0x05  0x068  1               0  ---  Specified Minimum Operating Temperature
0x06  =====  =               =  ===  == Transport Statistics (rev 1) ==
0x06  0x008  4             538  ---  Number of Hardware Resets
0x06  0x010  4             165  ---  Number of ASR Events
0x06  0x018  4               0  ---  Number of Interface CRC Errors
0xff  =====  =               =  ===  == Vendor Specific Statistics (rev 1) ==
                                |||_ C monitored condition met
                                ||__ D supports DSN
                                |___ N normalized value

Pending Defects log (GP Log 0x0c)
No Defects Logged

SATA Phy Event Counters (GP Log 0x11)
ID      Size     Value  Description
0x0001  2            0  Command failed due to ICRC error
0x0002  2            0  R_ERR response for data FIS
0x0003  2            0  R_ERR response for device-to-host data FIS
0x0004  2            0  R_ERR response for host-to-device data FIS
0x0005  2            0  R_ERR response for non-data FIS
0x0006  2            0  R_ERR response for device-to-host non-data FIS
0x0007  2            0  R_ERR response for host-to-device non-data FIS
0x0008  2            0  Device-to-host non-data FIS retries
0x0009  2          166  Transition from drive PhyRdy to drive PhyNRdy
0x000a  2          142  Device-to-host register FISes sent due to a COMRESET
0x000b  2            0  CRC errors within host-to-device FIS
0x000d  2            0  Non-CRC errors within host-to-device FIS

root@truenas[/home/truenas_admin]# smartctl -x /dev/sdb 
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.12.33-production+truenas] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     HUH721212ALE601
Serial Number:    8DJ4BRGH
LU WWN Device Id: 5 000cca 253de2c81
Firmware Version: LEGL0002
User Capacity:    12,000,138,625,024 bytes [12.0 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        Not in smartctl database 7.3/5528
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Thu Nov 27 09:26:57 2025 PST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is:   Unavailable
APM feature is:   Disabled
Rd look-ahead is: Enabled
Write cache is:   Enabled
DSN feature is:   Unavailable
ATA Security is:  Disabled, frozen [SEC2], Master PW ID: 0xfffd
Wt Cache Reorder: 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:      (   0)	The previous self-test routine completed
					without error or no self-test has ever 
					been run.
Total time to complete Offline 
data collection: 		(   87) 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: 	 (   1) minutes.
Extended self-test routine
recommended polling time: 	 (   1) 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          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  1 Raw_Read_Error_Rate     PO-R--   100   100   016    -    0
  2 Throughput_Performance  P-S---   132   132   054    -    96
  3 Spin_Up_Time            POS---   166   166   024    -    407 (Average 385)
  4 Start_Stop_Count        -O--C-   100   100   000    -    101
  5 Reallocated_Sector_Ct   PO--CK   100   100   005    -    0
  7 Seek_Error_Rate         PO-R--   100   100   067    -    0
  8 Seek_Time_Performance   P-S---   140   140   020    -    15
  9 Power_On_Hours          -O--C-   094   094   000    -    47676
 10 Spin_Retry_Count        PO--C-   100   100   060    -    0
 12 Power_Cycle_Count       -O--CK   100   100   000    -    62
 22 Unknown_Attribute       PO---K   100   100   025    -    100
 45 Unknown_Attribute       PO---K   100   100   001    -    1095233372415
192 Power-Off_Retract_Count -O--CK   100   100   000    -    1016
193 Load_Cycle_Count        -O--C-   100   100   000    -    1016
194 Temperature_Celsius     -O----   166   166   000    -    36 (Min/Max 20/56)
196 Reallocated_Event_Count -O--CK   100   100   000    -    0
197 Current_Pending_Sector  -O---K   100   100   000    -    0
198 Offline_Uncorrectable   ---R--   100   100   000    -    0
199 UDMA_CRC_Error_Count    -O-R--   200   200   000    -    0
231 Temperature_Celsius     -O--CK   100   100   000    -    0
241 Total_LBAs_Written      -O--C-   100   100   000    -    3588349314349
242 Total_LBAs_Read         -O--C-   100   100   000    -    6124138275133
                            ||||||_ K auto-keep
                            |||||__ C event count
                            ||||___ R error rate
                            |||____ S speed/performance
                            ||_____ O updated online
                            |______ P prefailure warning

General Purpose Log Directory Version 1
SMART           Log Directory Version 1 [multi-sector log support]
Address    Access  R/W   Size  Description
0x00       GPL,SL  R/O      1  Log Directory
0x01           SL  R/O      1  Summary SMART error log
0x02           SL  R/O      1  Comprehensive SMART error log
0x03       GPL     R/O      1  Ext. Comprehensive SMART error log
0x04       GPL     R/O    256  Device Statistics log
0x04       SL      R/O    255  Device Statistics log
0x06           SL  R/O      1  SMART self-test log
0x07       GPL     R/O      1  Extended self-test log
0x08       GPL     R/O      2  Power Conditions log
0x09           SL  R/W      1  Selective self-test log
0x0c       GPL     R/O   5501  Pending Defects log
0x10       GPL     R/O      1  NCQ Command Error log
0x11       GPL     R/O      1  SATA Phy Event Counters log
0x12       GPL     R/O      1  SATA NCQ Non-Data log
0x13       GPL     R/O      1  SATA NCQ Send and Receive log
0x15       GPL     R/W      1  Rebuild Assist log
0x21       GPL     R/O      1  Write stream error log
0x22       GPL     R/O      1  Read stream error log
0x24       GPL     R/O    256  Current Device Internal Status Data log
0x25       GPL     R/O    256  Saved Device Internal Status Data log
0x30       GPL,SL  R/O      9  IDENTIFY DEVICE data log
0x80       GPL     R/W    688  Host vendor specific log
0x81-0x9f  GPL,SL  R/W     16  Host vendor specific log
0xb2       GPL     VS     688  Device vendor specific log
0xc8       GPL     VS      12  Device vendor specific log
0xe0       GPL,SL  R/W      1  SCT Command/Status
0xe1       GPL,SL  R/W      1  SCT Data Transfer

SMART Extended Comprehensive Error Log Version: 1 (1 sectors)
No Errors Logged

SMART Extended Self-test Log Version: 1 (1 sectors)
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed without error       00%     47073         -
# 2  Short offline       Completed without error       00%     47049         -
# 3  Short offline       Completed without error       00%     47025         -
# 4  Short offline       Completed without error       00%     47001         -
# 5  Short offline       Completed without error       00%     46977         -
# 6  Short offline       Completed without error       00%     46953         -
# 7  Short offline       Completed without error       00%     46931         -
# 8  Short offline       Completed without error       00%     46905         -
# 9  Short offline       Completed without error       00%     46881         -
#10  Short offline       Completed without error       00%     46857         -
#11  Short offline       Completed without error       00%     46833         -
#12  Short offline       Completed without error       00%     46809         -
#13  Short offline       Completed without error       00%     46785         -
#14  Short offline       Completed without error       00%     46761         -
#15  Short offline       Completed without error       00%     46737         -
#16  Short offline       Completed without error       00%     46713         -
#17  Short offline       Completed without error       00%     46689         -
#18  Short offline       Completed without error       00%     46665         -
#19  Short offline       Completed without error       00%     46641         -

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.

SCT Status Version:                  3
SCT Version (vendor specific):       256 (0x0100)
Device State:                        Active (0)
Current Temperature:                    36 Celsius
Power Cycle Min/Max Temperature:     34/38 Celsius
Lifetime    Min/Max Temperature:     20/56 Celsius
Under/Over Temperature Limit Count:   0/0

SCT Temperature History Version:     2
Temperature Sampling Period:         1 minute
Temperature Logging Interval:        1 minute
Min/Max recommended Temperature:      0/60 Celsius
Min/Max Temperature Limit:           -40/70 Celsius
Temperature History Size (Index):    128 (49)

Index    Estimated Time   Temperature Celsius
  50    2025-11-27 07:19    35  ****************
 ...    ..( 19 skipped).    ..  ****************
  70    2025-11-27 07:39    35  ****************
  71    2025-11-27 07:40    36  *****************
  72    2025-11-27 07:41    35  ****************
  73    2025-11-27 07:42    36  *****************
 ...    ..( 34 skipped).    ..  *****************
 108    2025-11-27 08:17    36  *****************
 109    2025-11-27 08:18    35  ****************
 110    2025-11-27 08:19    36  *****************
 111    2025-11-27 08:20    35  ****************
 ...    ..(  3 skipped).    ..  ****************
 115    2025-11-27 08:24    35  ****************
 116    2025-11-27 08:25    36  *****************
 117    2025-11-27 08:26    36  *****************
 118    2025-11-27 08:27    36  *****************
 119    2025-11-27 08:28    35  ****************
 ...    ..( 16 skipped).    ..  ****************
   8    2025-11-27 08:45    35  ****************
   9    2025-11-27 08:46    36  *****************
  10    2025-11-27 08:47    36  *****************
  11    2025-11-27 08:48    36  *****************
  12    2025-11-27 08:49    35  ****************
  13    2025-11-27 08:50    36  *****************
 ...    ..( 34 skipped).    ..  *****************
  48    2025-11-27 09:25    36  *****************
  49    2025-11-27 09:26    35  ****************

SCT Error Recovery Control:
           Read: Disabled
          Write: Disabled

Device Statistics (GP Log 0x04)
Page  Offset Size        Value Flags Description
0x01  =====  =               =  ===  == General Statistics (rev 1) ==
0x01  0x008  4              62  ---  Lifetime Power-On Resets
0x01  0x010  4           47676  ---  Power-on Hours
0x01  0x018  6   3588349314349  ---  Logical Sectors Written
0x01  0x020  6      5180533418  ---  Number of Write Commands
0x01  0x028  6   6124138275133  ---  Logical Sectors Read
0x01  0x030  6      9400622488  ---  Number of Read Commands
0x01  0x038  6    171634531750  ---  Date and Time TimeStamp
0x03  =====  =               =  ===  == Rotating Media Statistics (rev 1) ==
0x03  0x008  4           47338  ---  Spindle Motor Power-on Hours
0x03  0x010  4           47338  ---  Head Flying Hours
0x03  0x018  4            1016  ---  Head Load Events
0x03  0x020  4               0  ---  Number of Reallocated Logical Sectors
0x03  0x028  4              26  ---  Read Recovery Attempts
0x03  0x030  4               0  ---  Number of Mechanical Start Failures
0x04  =====  =               =  ===  == General Errors Statistics (rev 1) ==
0x04  0x008  4               0  ---  Number of Reported Uncorrectable Errors
0x04  0x010  4               0  ---  Resets Between Cmd Acceptance and Completion
0x05  =====  =               =  ===  == Temperature Statistics (rev 1) ==
0x05  0x008  1              36  ---  Current Temperature
0x05  0x010  1              34  N--  Average Short Term Temperature
0x05  0x018  1              36  N--  Average Long Term Temperature
0x05  0x020  1              56  ---  Highest Temperature
0x05  0x028  1              20  ---  Lowest Temperature
0x05  0x030  1              55  N--  Highest Average Short Term Temperature
0x05  0x038  1              24  N--  Lowest Average Short Term Temperature
0x05  0x040  1              53  N--  Highest Average Long Term Temperature
0x05  0x048  1              25  N--  Lowest Average Long Term Temperature
0x05  0x050  4               0  ---  Time in Over-Temperature
0x05  0x058  1              60  ---  Specified Maximum Operating Temperature
0x05  0x060  4               0  ---  Time in Under-Temperature
0x05  0x068  1               0  ---  Specified Minimum Operating Temperature
0x06  =====  =               =  ===  == Transport Statistics (rev 1) ==
0x06  0x008  4             544  ---  Number of Hardware Resets
0x06  0x010  4             170  ---  Number of ASR Events
0x06  0x018  4               0  ---  Number of Interface CRC Errors
0xff  =====  =               =  ===  == Vendor Specific Statistics (rev 1) ==
                                |||_ C monitored condition met
                                ||__ D supports DSN
                                |___ N normalized value

Pending Defects log (GP Log 0x0c)
No Defects Logged

SATA Phy Event Counters (GP Log 0x11)
ID      Size     Value  Description
0x0001  2            0  Command failed due to ICRC error
0x0002  2            0  R_ERR response for data FIS
0x0003  2            0  R_ERR response for device-to-host data FIS
0x0004  2            0  R_ERR response for host-to-device data FIS
0x0005  2            0  R_ERR response for non-data FIS
0x0006  2            0  R_ERR response for device-to-host non-data FIS
0x0007  2            0  R_ERR response for host-to-device non-data FIS
0x0008  2            0  Device-to-host non-data FIS retries
0x0009  2          167  Transition from drive PhyRdy to drive PhyNRdy
0x000a  2          142  Device-to-host register FISes sent due to a COMRESET
0x000b  2            0  CRC errors within host-to-device FIS
0x000d  2            0  Non-CRC errors within host-to-device FIS

root@truenas[/home/truenas_admin]#

To @etorix ‘s point earlier - is there a relatively simple method by which I could attempt to delete the files with errors? Right now, as far as I can tell, I can’t interact with the data even though the pool is imported. I suppose I could probably navigate via the CLI and ‘rm -R’ affected content?

9

You can’t remove any corrupt file, while the pool is imported Read Only.

With this import option, -R /mnt, you should be able to browse the entire pool, except any zVols, (if any). Any file with bad blocks will return either errors if copy attempted. Or return random / zero for that hole in the file.

But, back to recovery. Without a good reason why the pool became corrupt, re-activating it on the same hardware may simply lead to more corruption. (Well, in the case of the single disk pool, fastboi, that could just be a bad block on the media.)

10

Sorry for the lack of understanding here, just want to make sure I don’t do anything that’s going to cause more problems than it solves. I have attempted zpool import -R /mnt bigboi several times, and it fails to import the pool. Was your recommendation to try that same command on different hardware, and see if it imports successfully there instead? I don’t have any other Linux machines in the house (and certainly no machines with ZFS), so that’d be a pretty extended wait before I could try. But if that’s the next step, I’m happy to give it a go when I’m able.

11

No long test has been run, but the drives are healthy, as far we can tell. So that’s good.

I have no idea why the pool would not import without “readonly=on”.
So, if you have enough storage at hand, my suggestion would be to copy everything you can (and care about) and then destroy the pool.

But it is worrying that two pools grew errors, and I’m not inclined to put it to “the NVMe just had a bad sector at the same time that the SATA controller threw a hissy fit because of a passing cosmic ray”. There’s a question of what to restore to, and, somehow, it would help if, say, Memtest revealed that one stick is defective.

12

Ah! Yeah, I definitely misunderstood. I did import the pool as read only, with the -R /mnt flags, and I am able to navigate the directory structure via CLI. I haven’t tried modifying or removing any files, though, so I wasn’t sure if that would work, since I can’t modify permissions or access any content via GUI. Sounds like the best bet, then, is to start copying content off of it as I’m able, then destroy and recreate the pool. (And maybe both data pools, given errors on fastboi as well?)

Regarding memtest - it’s been a long time since I’ve done that, does it still require a bootable USB? Or is there a tool I could install via CLI and run from the shell?

13

Yes for needing a bootable usb. There are a few motherboards I’ve seen (Asus) that have a memtest option baked into the bios - so very likely you’ll be making a bootable usb.