A few months ago one of my drives, old drive 6, was starting to show errors on SMART report so I bought a WD 12TB external to shuck to replace it. My parity drive was a 10TB, its now the new drive 6. Once the drive came in I ran a preclear and it passed. I then stopped the array, removed the old drive 6, did new a new config and moved the 10TB to the Drive 6 slot. Started the array up and it worked fine. Took the array down and put the 12TB as the parity. Brought the array up and it appeared to be fine until about 3/4 of the way through the parity check and I started getting a lot of errors on parity and I think Drive 1 and 12. Restarted the server and it showed the parity being bad but all the array was working fine. Over the past few weeks when I've had time I've tried rebuilding the parity but always get the same issue of at some part through the rebuild it gets a lot of errors and locks up the Main and Dashboard screens on the server and I have to push the reset button the case to take it down.

This weekend I finally had a chance to replace the SATA cable for the parity and Drive 1. I did a new config but kept the cache and data drive configs. Set the parity drive and then started it up and it looked to be fine for about an hour. I started transferring files to an external drive, WD Elements, after a few hours I started getting a bunch of errors. I did get the diagnostics pulled off, see attached. 

I do have two PCI to SATA cards and the Drive 1 and 12 are attached to. The parity drive is on motherboard. I didn't have any issues until I recently so I was hoping the PCI cards are still good. I know they Marvell and those don't always play well with Unraid. I was hoping to hold off until later next year to replace the card with an LSI SAS card. 

tower-diagnostics-20191208-1314.zip

Looks like a problem with the Marvell 9230 controller, they are a known problem and can go wrong at any time.

Ok, thanks for verifying. That's twice Marvell drivers have caused me issues. Think this should be the last of them. On to LSI!

Bought and installed the LSI card, no issues since. My parity build is faster than with Marvel cards, no surprise. Just wish I hadn't waited so long to buy one.