Sync errors

[phreakedout]

Hey guys,

 

So I recently went through a procedure to replace/swap one of the parity disks for a much larger disk (8TB->18TB).  Everything seems to be running fine afterwards, but decided to do a parity check before going through a similar procedure for the other parity disk.  It's taking a good long while, but I'm running docker during this time so this is to be expected.  Last I looked I was around 6TB into this and I think I had 1 sync error detected.  No big deal.  Now I am at ~10.5TB in and its throwing TONS of sync errors. 

 

My guess here is that because the parity disks sizes don't match, every bit of data past the 8TB size of the one parity disk can't sync to the smaller disk resulting in a sync error.  Am I right in thinking this?

unraid-diagnostics-20220311-1805.zip

[JorgeB]

8 hours ago, phreakedout said:

and I think I had 1 sync error detected.  No big deal. 

That is a big deal, only number of acceptable sync errors is 0.

 

8 hours ago, phreakedout said:

Now I am at ~10.5TB in and its throwing TONS of sync errors. 

Except for one the sync errors started right at the 8TB mark, this suggests the initial sync or not correct or you did a parity swap, this sometimes results in a pesky bug that doesn't correctly zero out the reaming of the drive past the initial parity size.

 

[phreakedout]

Fair enough on both counts.  Recommended Fix?

[JorgeB]

Run a correcting check then a non correcting one to make result is 0.

[phreakedout]

Correcting Check in progress.  I'll let you know how it goes.  Thanks for the advice.

[phreakedout]

Update:

 

Currently at 7.1TB complete, and the 1 error has been corrected.  I suspect I'll soon see a flood of corrected errors as it zeros out the rest of the 18TB disk.  So far so good...

[phreakedout]

As expected it started correcting droves errors at precisely the 8TB mark.  Hopefully all goes well.  

[phreakedout]

Yup, this process resolved the issues.  Quite some time later, I have completed the correcting check with an insane number of errors corrected (~2 billion).  The data is healthy having done a pretty extensive spot check of the files, and also did a second non-correcting check with zero sync errors found.  Good stuff. Thanks much @JorgeB