Just upgraded my parity drive from a 2Tb to a 4Tb, unRaid copied parity from the original disk to the new disk and started the array, parity was valid.

 

Ran a parity check to make sure all was good and it was ticking along just fine until it went passed the 2Tb mark, now its showing (at this point) 52951715 parity sync errors and climbing.

 

Is this just because it needs to write something to the other half of the 4tb disk?

 

unRaid 6.0-beta14b

Someone else reported they saw this behaviour but they let it complete and correct the errors found.  The next parity check found 0 errors.

 

It sounds as if there might be some sort of bug present when upgrading a parity drive to a larger size where the part of the parity drive that is beyond the size of the largest data disk does not get written (as I believe it should after the parity copy part completed).  The subsequent check therefore finds errors in this part of the parity disk, but corrects them so they no longer occur in the future.

Makes sense.

 

Its crawling along at 16.8 MB/sec so its going to be a while before it completes!

If there isn't one, you should create a defect in the defects forum.

Agree ... this is clearly a defect in v6's code for upgrading parity.  Neither v4.7 (when upgrading from smaller drives to larger drives that couldn't exceed 2TB) nor v5 had this issue.

 

Just let it finish, then run another parity check to confirm all is okay ... the next parity check should show zero errors.

 

Will do. Right now its corrected 219833340 sync errors lol.

The good news is that since it passed the 2TB point before you started seeing these, it's clear what's going on -- the parity disk itself has simply never been cleared beyond that point.  Normally that would have all been zeroed as part of the parity upgrade ... but clearly that didn't happen in your case.

 

The next parity check should have no errors -- but that's a fair number of hours in the future