I really don't see anything wrong. Is it the bit after "== Disk /dev/sdf has NOT been precleared successfully" and, if so, what does it mean?

 

== WDCWD50EFRX-68L0BN1   WD-WX41D75CTE49
== Disk /dev/sdf has NOT been precleared successfully
== skip=207800 count=200 bs=1000448 returned 04160 instead of 00000 skip=208200                                                                                                                                                              count=200 bs=1000448 returned 19732 instead of 00000 skip=208800 count=200 bs=10                                                                                                                                                             00448 returned 13890 instead of 00000 skip=252600 count=200 bs=1000448 returned                                                                                                                                                              35527 instead of 00000 skip=259400 count=200 bs=1000448 returned 58542 instead o                                                                                                                                                             f 00000 skip=280400 count=200 bs=1000448 returned 31266 instead of 00000 skip=48                                                                                                                                                             6400 count=200 bs=1000448 returned 14717 instead of 00000 skip=521200 count=200                                                                                                                                                              bs=1000448 returned 46757 instead of 00000 skip=542200 count=200 bs=1000448 retu                                                                                                                                                             rned 62811 instead of 00000 skip=549200 count=200 bs=1000448 returned 01027 inst                                                                                                                                                             ead of 00000
============================================================================
** Changed attributes in files: /tmp/smart_start_sdf  /tmp/smart_finish_sdf
                ATTRIBUTE   NEW_VAL OLD_VAL FAILURE_THRESHOLD STATUS      RAW_VA                                                                                                                                                             LUE
      Temperature_Celsius =   117     116            0        ok          35
No SMART attributes are FAILING_NOW

0 sectors were pending re-allocation before the start of the preclear.
0 sectors were pending re-allocation after pre-read in cycle 1 of 1.
0 sectors were pending re-allocation after zero of disk in cycle 1 of 1.
0 sectors are pending re-allocation at the end of the preclear,
    the number of sectors pending re-allocation did not change.
0 sectors had been re-allocated before the start of the preclear.
0 sectors are re-allocated at the end of the preclear,
    the number of sectors re-allocated did not change.

 

Basically, I guess I'm just not seeing the error here. Also, the entire point of the preclear was to avoid taking the array offline for the ~2 days it took to get the drive added through the GUI. Is there some other way to avoid that?

 

Added: Apparently I can add without downing the array the entire time it processes the disks, which I'd swear wasn't an option.

 

I'm still curious about the preclear failure, though, and what the actual failure was.

Added: Apparently I can add without downing the array the entire time it processes the disks, which I'd swear wasn't an option.

 

I'm still curious about the preclear failure, though, and what the actual failure was.

 

Looks to me like the read verification phase found something that was not all zeroes although it should have been.

 

You should absolutely not add the drive to the array in that state as it was not properly precleared. Mostly cleared is not enough. If you add the drive, your parity will be incorrect. You should also figure out why it failed. Bad disk perhaps?

You'd have to look at the pre-clear script to find out exactly what's going on but my guess is this:

 

The skip, count and bs values are all parameters for the dd command which is being used to read and write the disk at block level by the script. Usually a Linux command returns the value 0 if it is successful, or non-zero to indicate a failure. So the command appears to be failing. The reason is unlikely to be due to a bug because the pre-clear script is tried and tested, so it's looking as though you have a problem with the disk, or maybe the cabling, or the controller. Run an extended SMART self-test on the disk and post your diagnostics.

 

unRAID 6.2.0-beta added the capability to add an uncleared disk without taking the array off-line but if you have a bad disk you want to know about it.

 

Added: Apparently I can add without downing the array the entire time it processes the disks, which I'd swear wasn't an option.

 

I'm still curious about the preclear failure, though, and what the actual failure was.

I think it means that the post read check did not get the expected values.  I would be very reluctant to use a disk if I could get silent read or write errors with no indication at the hardware level of any error.

 

Might want to redo the preclear to,see,if you get better results the next time.

Is there any other check I can run now that it's been added to the array?

The extended SMART self-test is non-destructive.