Attaching my diagnostics file. Currently getting around 9 mb/sec on a 4TB parity sync which says it'll take 4 days to complete. A couple of days ago, I moved many files from a 2TB WD green drive via midnight commander to other drives on the array. I then removed that drive, did a "new config" and checked the "parity is valid". Any thoughts why this sync is SO SLOW and why I currently see  45 million + sync corrections? I just got 2 new WD 4TB RED drives that are pre-cleared and ready to go into the array after I do this parity sync.

unraid-diagnostics-20160418-1518.zip

I then removed that drive, did a "new config" and checked the "parity is valid". Any thoughts why this sync is SO SLOW and why I currently see  45 million + sync corrections?

This, exactly. Parity WAS NOT valid. Do the new config again, but DON'T check the "parity is valid". You need to build parity for the current set of drives, then check it when it is finished building.

I then removed that drive, did a "new config" and checked the "parity is valid". Any thoughts why this sync is SO SLOW and why I currently see  45 million + sync corrections?

This, exactly. Parity WAS NOT valid. Do the new config again, but DON'T check the "parity is valid". You need to build parity for the current set of drives, then check it when it is finished building.

 

Thank you. I've cancelled the current check, done the new config again, started the array WITHOUT checking the "parity is valid" box and the parity check is underway again. It's ~ 35 mb / sec now, but that's about what it was when I began the check this AM. I'll keep an eye on it. Thank you again.

I'm unclear why you didn't include the 2 new drives since you are building parity from scratch anyway. Since they are precleared, it won't make much difference, just wondering is all.