I checked my server the other day and noticed an "array health report [FAIL]" warning and 107 errors on the parity disk and disk 14 had lots or relocated sectors. I ran a parity test which came up fine but it still said there had been 107 errors on the main screen.

 

I've got a 2TB hot spare to replace disk 14 which keeps relocating sectors nearly every time I log in. I'm on a 2nd of 3 cycles preclearing a 4TB to replace parity.

 

I went on this afternoon to see how the preclear was going on and the errors weren't there anymore, it now says 0.

 

Does parity actually need replacing now it says 0?

 

If I have to replace both which do I replace 1st, disk 14 or the parity disk?

 

Thanks

There's a big difference between the errors column on the Main tab and the actual health of the drive(s) in question (although they are often related)

 

The errors column is reset with every stop/start of the array and is merely a running counter of the number of read errors the drive has thrown that required reconstruction from the rest of the array drives.

 

SMART reports are what really matters in cases like this.  You should really post your diagnostics

So should I run SMART tests on the parity and disk 14 and post here?

So should I run SMART tests on the parity and disk 14 and post here?

You should really post your diagnostics

Tools - Diagnostics. Post complete zip.

Here we go.

tower-diagnostics-20160426-0729.zip

Parity errors were probably caused by this:

 

Device Model:     ST4000DM000-1F2168
Serial Number:    W300PBWN
183 Runtime_Bad_Block       0x0032   099   099   000    Old_age   Always       -       1
187 Reported_Uncorrect      0x0032   099   099   000    Old_age   Always       -       1

 

Error was recent:

 

9 Power_On_Hours          0x0032   087   087   000    Old_age   Always       -       11693

Error 1 occurred at disk power-on lifetime: 11089 hours (462 days + 1 hours)

 

But it passed a extended test after that, so the disk should be ok for now:

 

Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed without error       00%     11347         -

 

 

You have some disks with UDMA_CRC errors, two of the with very high counts, this could be old errors, but would should monitor them for a few weeks, a avlue increase of 2 or more usually means a bad SATA cable.

 

Device Model:     ST32000542AS
Serial Number:    5XW0N2Q3
199 UDMA_CRC_Error_Count    0x003e   200   199   000    Old_age   Always       -       12721

Device Model:     ST32000542AS
Serial Number:    6XW1QTW0
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       13573

Device Model:     ST32000542AS
Serial Number:    5XW199NW
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       45

 

Regarding disk14, reallocated sectors by themselves don't indicate a bad disk, but it could be the start of more issues to come, many don't like having disks like that in the array, but it's up to you, you should at least do an extend SMART test.

 

After, you should also do a parity check.

Thanks for that.

I will swap disk 14 as it's just sat there and I have a few of them.

Would it be worth replacing the sata cables?

 

To keep an eye on it do I just run diagnostics in a few week's and compare the numbers?

To keep an eye on it do I just run diagnostics in a few week's and compare the numbers?

 

Yes, these could be old errors as the value is never reset, so check them once a week for a couple of weeks to confirm if they are stable.

Thank you for everyone's help, much appreciated!