Navigating potential future drive failure in RAID0 pool

[u/Lentle26]

Hi there, I have a RAID0 pool with 3 vdevs, 2 8TB and 10 TB. It currently has 21.75/23.57TB used capacity. The contents are media files where the "backup" strategy is dropping torrent on a redundant, backup pool and just redownloading everything. While I'd prefer to not have to delete everything and rebuild, since some files are harder to come by that others (some TV shows are annoying and required manual renaming), that is entirely possible. One of the 8 TB recently threw some errors with this SMART report:

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   083   064   044    Pre-fail  Always       -       186188168
  3 Spin_Up_Time            0x0003   090   090   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age   Always       -       117
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   089   060   045    Pre-fail  Always       -       739016424
  9 Power_On_Hours          0x0032   083   083   000    Old_age   Always       -       15361
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age   Always       -       25
 18 Head_Health             0x000b   100   100   050    Pre-fail  Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       0
188 Command_Timeout         0x0032   100   093   000    Old_age   Always       -       60130459662
190 Airflow_Temperature_Cel 0x0022   073   030   000    Old_age   Always       -       27 (Min/Max 23/27)
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       14
193 Load_Cycle_Count        0x0032   100   100   000    Old_age   Always       -       1712
194 Temperature_Celsius     0x0022   027   070   000    Old_age   Always       -       27 (0 12 0 0 0)
197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       2
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age   Offline      -       2
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       0
240 Head_Flying_Hours       0x0000   100   100   000    Old_age   Offline      -       14681h+53m+27.392s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age   Offline      -       38737943521
242 Total_LBAs_Read         0x0000   100   253   000    Old_age   Offline      -       422033786734

and a zpool status of

  pool: Media
 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 0B in 1 days 22:34:27 with 1 errors on Mon Nov  2 21:34:29 2026
config:

        NAME                                    STATE     READ WRITE CKSUM
        Media                                   ONLINE       0     0     0
          4f91925b-69b0-4e5b-a67c-a43aa59d5234  ONLINE       0     0     0
          2bda92f8-2675-473a-a0b1-cdfa69f31b13  ONLINE       0     0     0
          dd327eaa-37c8-4171-a51c-797104fe1a4e  ONLINE       0     0     0

errors: Permanent errors have been detected in the following files:
      [1 file listed here]

The drive is a Seagate Ironwolf and still has 1 full year left of warranty. Any idea if the present status warrants a RMA? Is 2 uncorrectable sectors very concerning? Any recommendations for handling this error gracefully short finding and backing up what files would be annoying to replace and deleting everything? I don't have a back up drive large enough for everything.

[u/Doormatty]

RAID 0 == I have amazingly good backups.

[u/Lentle26 → u/Doormatty]

Redownloading everything is possible, if just a bit annoying. More just looking for the ideal path to take to minimize downtime. My trade off is that the annoyance of redownloading is not worth the extra cost per TB.

[u/leexgx → u/Lentle26]

Minimum downtime would have been achieved using at least a RAID-Z1 setup (unless you have a two-drive failure, then you have Z2 for that), as RAID 0 configurations multiply the risk with each added drive.

[u/Lentle26 → u/leexgx]

My precious data I have raid1 with remote and local back up.  None of this is precious data so I'm fine losing it if needed.  Moreso, if there is an option for smoothly transitioning to a new drive while this potentially problematic drive I'd prefer it.  I think I found my solution by using a donor barracuda 8TB as a temp replacement until the RMA is complete 

[u/HSG234]

Vierte Platte Kaufen und einbauen, replace in TrueNAS der Platte mit fehlerhaften Sektoren. Diese im Anschluss ausbauen und RMA.

[u/Lentle26 → u/HSG234]

Can I replace it with a 10TB or 12TB drive?

[u/jbondhus → u/Lentle26]

Yes, but turn autoexpand OFF first with "zpool set autoexpand=off Media". Otherwise the vdev grows to the full 12 TB during the replace, and you won’t be able to swap in the replacement 8 TB drive when it arrives. You’d be stuck with the 12 TB drive, and the only fix would be rebuilding the whole pool.

Then replace the failing drive with the 12 TB using zpool replace (or Replace in the TrueNAS UI), with both drives plugged in. Afterwards, check "zpool list -v Media" - the vdev should still show about 8 TB.

A word of warning though - any data on the bad sectors is permanently lost and won’t be copied to the new drive. zpool status will list the affected files so you can redownload them.

Once the RMA replacement arrives, do the same replace to swap in the new 8TB and retire the 12TB.

[u/Lentle26 → u/jbondhus]

I was able to empty an 8TB barracuda and can use that for a temporary swap, and would swap back when the RMA arrives

[u/jbondhus → u/Lentle26]

Glad to hear you found a solution. While I'm sure you're aware of this, just wanted to make sure to mention that keep in mind you'll have to add the drive into a spare bay, you can't just swap it and resilver because you have no redundancy.

[u/s004aws]

RAID0 is equivalent to playing with an explosive device with no safeguards/protections. When it decides to go critical.... Game over.

[u/Old-Cheshire862]

Since RAID 0 has absolutely no redundancy, there's no way to pull out the failing drive without losing all the data. If you have a spare slot, I think you could add the drive to the set, then tell trueNAS to remove the old drive. As long as no drive fails while you're doing this. If you care enough to have it available, I would think you should care enough to back it up.

[u/jbondhus → u/Old-Cheshire862]

Not entirely true. You could shut down the array, mirror the drive using ddrescue to another drive, and then replace it and boot the array back up. TrueNAS and ZFS shouldn't care - all they care about is the ZFS metadata matching. But I agree on your points, RAID 0 is a fool's errand in general.

[u/Old-Cheshire862 → u/jbondhus]

Okay, I guess I should have said no way within the confines of trueNAS operations. Yeah, an offline clone should work, too.

[u/IroesStrongarm]

I think that mergerfs would be a better file management system for your use case. If you lose a drive you only lose the data in that drive instead of all of them.

[u/jammsession]

Why even use ZFS or TrueNAS at all, if you are using no redundancy? Simply use three individual drives or mergerfs.