Having a hell of a time preclearing two new 28tb drives. First drive started reallocating sectors so I pulled that to return. Drive 2 failed step 4 the first time I ran it. After swapping it to a different bay, it successfully finished step 1, but essentially never started step 2. Once step 2 began, it was at 0 mb/s or 1 mb/s but never any faster. After ~12 hours it was still at 0% complete. Diagnostics attached.

photoserver-diagnostics-20260314-0610.zip

Constant ATA errors on sbd, which doesn't show on SMART so I assume it dropped offline. Check/replace cables for that device, then post new diags.

Dammit, I loaded the wrong diagnostics file. Sorry about that.

photoserver-diagnostics-20260316-0541.zip

Still ATA issues, this disk:

Device Model: ST28000NT000-4AB103

Serial Number: K1S09QSQ

ok, moved the drive to a different bay again. Was able to finish step 3 but then failed step 4 with the following log:

In Summary:

Drive One had reallocated sectors during preclear, pulled that drive to return.

Drive Two (This One) has failed step four twice now. First time was due to connection problems that filled the log. I swapped bays to use a different cable and started again.

Preclear Log

Mar 16 08:51:50 preclear_disk_K1S09QSQ_9418: Preclear Disk Version: 1.0.31

Mar 16 08:51:50 preclear_disk_K1S09QSQ_9418: Restoring previous instance of preclear

Mar 16 08:51:51 preclear_disk_K1S09QSQ_9418: Disk size: 28001039286272

Mar 16 08:51:51 preclear_disk_K1S09QSQ_9418: Disk blocks: 6836191232

Mar 16 08:51:51 preclear_disk_K1S09QSQ_9418: Blocks (512 bytes): 54689529856

Mar 16 08:51:51 preclear_disk_K1S09QSQ_9418: Block size: 4096

Mar 16 08:51:51 preclear_disk_K1S09QSQ_9418: Start sector: 0

Mar 16 08:51:52 preclear_disk_K1S09QSQ_9418: Zeroing: zeroing the disk started 1 of 5 retries...

Mar 16 08:51:52 preclear_disk_K1S09QSQ_9418: Continuing disk write on byte 36310089728

Mar 16 09:31:43 preclear_disk_K1S09QSQ_9418: Zeroing: progress - 25% zeroed @ 2959 MB/s

Mar 16 10:12:25 preclear_disk_K1S09QSQ_9418: Zeroing: progress - 50% zeroed @ 2946 MB/s

Mar 16 10:53:53 preclear_disk_K1S09QSQ_9418: Zeroing: progress - 75% zeroed @ 2645 MB/s

Mar 16 11:35:18 preclear_disk_K1S09QSQ_9418: Zeroing: progress - 100% zeroed @ 1610 MB/s

Mar 16 11:35:20 preclear_disk_K1S09QSQ_9418: Zeroing: zeroing the disk completed!

Mar 16 11:35:20 preclear_disk_K1S09QSQ_9418: Signature: writing signature...

Mar 16 11:35:21 preclear_disk_K1S09QSQ_9418: Signature: verifying Unraid's signature on the MBR ...

Mar 16 11:35:21 preclear_disk_K1S09QSQ_9418: Signature: Unraid preclear signature is invalid!

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Error:

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.:

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: ATTRIBUTE INITIAL NOW STATUS

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Reallocated_Sector_Ct 0 0 -

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Power_On_Hours 167 170 Up 3

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Reported_Uncorrect 0 0 -

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Airflow_Temperature_Cel 30 40 Up 10

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Current_Pending_Sector 0 0 -

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: Offline_Uncorrectable 0 0 -

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.: UDMA_CRC_Error_Count 1 1 -

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: S.M.A.R.T.:

Mar 16 11:35:22 preclear_disk_K1S09QSQ_9418: error encountered, exiting ...

photoserver-diagnostics-20260316-1145.zip

Device Model: ST28000NT000-4AB103

Serial Number: K1S09QSQ

There are still errors logged, same disk, if you swapped slots, it may be a bad disk.

I just swapped this drive into my other server and set preclear to just verify signature and it gave the same errors. Looks like I'm unable to run SMART reports on the drive until it's been added to the array. Is that correct? Guessing maybe both of these drives came from a bad batch of drives but at least I can still return them.

11 minutes ago, johngalt said:

Looks like I'm unable to run SMART reports on the drive until it's been added to the array. Is that correct? Guessing maybe both of these drives came from a bad batch of drives but at least I can still return them.

The diagnostics should include SMART reports for all drives regardless of whether they are in the array.