OpenZFS is amazing

[grahamperrin]

A single-disk pool on an old mobile hard disk drive on USB.

Permanent errors, scrubbed away in less than one second:

root@mowa219-gjp4 ~# zpool status -v Transcend
  pool: Transcend
 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: resilvered 1.05M in 00:00:01 with 0 errors on Tue Jun 16 03:08:55 2026
config:

        NAME                                         STATE     READ WRITE CKSUM
        Transcend                                    ONLINE       0     0     0
          ata-ST1000LM024_HN-M101MBB_S2S6J9FD203745  ONLINE       0     0     0

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

        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/2026-05-03T16-06-33-559788000Z.nvram
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/2025-12-07T23-22-45-302819000Z.nvram
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/FreeBSD 13, 14, 15, 16.vbox-prev
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/2026-05-12T11-15-03-204545000Z.nvram
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Logs
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/{63bd4254-f125-4be2-a30f-701ea74498e4}.vdi
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/2026-06-16T01-16-17-580025000Z.nvram
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/2026-06-16T01-58-16-593213000Z.nvram
root@mowa219-gjp4 ~# zpool scrub -e Transcend
root@mowa219-gjp4 ~# zpool status -v Transcend
  pool: Transcend
 state: ONLINE
 scrub: scrubbed 16 error blocks in 0 days 00:00:00 on Tue Jun 16 03:10:28 2026
  scan: resilvered 1.05M in 00:00:01 with 0 errors on Tue Jun 16 03:08:55 2026
config:

        NAME                                         STATE     READ WRITE CKSUM
        Transcend                                    ONLINE       0     0     0
          ata-ST1000LM024_HN-M101MBB_S2S6J9FD203745  ONLINE       0     0     0

errors: No known data errors
root@mowa219-gjp4 ~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 26.04 LTS
Release:        26.04
Codename:       resolute
root@mowa219-gjp4 ~# zfs version
zfs-2.4.1-1ubuntu5
zfs-kmod-2.4.1-1ubuntu5
root@mowa219-gjp4 ~# zpool list -v
NAME                                                  SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
Transcend                                             928G   658G   270G        -         -    46%    70%  1.00x    ONLINE  -
  ata-ST1000LM024_HN-M101MBB_S2S6J9FD203745           932G   658G   270G        -         -    46%  70.9%      -    ONLINE        -
bpool                                                1.88G   385M  1.50G        -         -     9%    20%  1.00x    ONLINE  -
  ata-Samsung_SSD_870_QVO_1TB_S5RRNF0TB68850Y-part2     2G   385M  1.50G        -         -     9%  20.1%      -    ONLINE        -
rpool                                                 920G   680G   240G        -         -    58%    73%  1.00x    ONLINE  -
  wwn-0x5002538f42b2daed-part4                        920G   680G   240G        -         -    58%  73.9%      -    ONLINE        -
root@mowa219-gjp4 ~#

Kubuntu 26.04.

[grahamperrin]

Following a later incident, option -e seemed problematic, twice.

In both cases, the command line became unresponsive, I had to shut down the system.

The second attempt:

root@mowa219-gjp4 ~# zpool import Transcend && zfs load-key -L file:////home/grahamperrin/Documents/personal/VirtualBox.key Transcend/VirtualBox && zfs mount Transcend/VirtualBox
root@mowa219-gjp4 ~# zpool status -v Transcend
  pool: Transcend
 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: resilvered 672K in 00:00:01 with 0 errors on Tue Jun 16 05:26:31 2026
config:

        NAME                                         STATE     READ WRITE CKSUM
        Transcend                                    ONLINE       0     0     0
          ata-ST1000LM024_HN-M101MBB_S2S6J9FD203745  ONLINE       0     0     0

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

        Transcend/VirtualBox:<0x0>
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Snapshots/{bdb3e817-1573-44b4-aabb-cd0f849b3e85}.vdi
        /media/t1000/VirtualBox/BSD/FreeBSD/FreeBSD 13, 14, 15, 16/Logs/VBox.log
root@mowa219-gjp4 ~# zpool scrub -e Transcend
^T^T^C

Thankfully, a full scrub succeeded and then option -e was OK:

root@mowa219-gjp4 ~# zpool status -v Transcend
  pool: Transcend
 state: ONLINE
  scan: scrub repaired 0B in 03:08:31 with 0 errors on Wed Jun 17 21:07:55 2026
config:

        NAME                                         STATE     READ WRITE CKSUM
        Transcend                                    ONLINE       0     0     0
          ata-ST1000LM024_HN-M101MBB_S2S6J9FD203745  ONLINE       0     0     0

errors: No known data errors
root@mowa219-gjp4 ~# zpool scrub -e Transcend
root@mowa219-gjp4 ~# 

[CiotBSD]

Hummm… hardware corruption?!

[grahamperrin]

hardware corruption?!

Sometimes, errors occur when the USB connection is physically disturbed.

Other times, there's no obvious explanation. I might be hands-off, with my cat nowhere near, at the time.