My parity drive started showing SMART errors.  I have an identical, pre-cleared drive as a backup, so I followed the steps to replace the existing parity drive found on the wiki (and on these forums):  (1) stop the array; (2) unassign the parity drive; (3) shutdown the server; (4) remove the old parity drive and replace with the new parity drive; (5) boot up the server; (6) assign the parity drive to the new drive; (7) rebuild the parity.

 

However, when I get to step 6, it just says "wrong" and won't let me start up the array with the new drive selected.  What's wrong here?  I suppose one option would be to copy the parity from the old drive to the new (not exactly sure how to do this as I haven't looked into it too deeply), but given the SMART errors that were popping up on the old drive it makes the most sense (to me) to rebuild the parity.

 

FYI, Disk 3 is the new parity drive, but was originally part of the array (it has since now been pre-cleared).  Not sure if that matters, but the plan is to replace that drive as well later.

 

Thank you!

1 minute ago, sewersurfin said:

FYI, Disk 3 is the new parity drive, but was originally part of the array (it has since now been pre-cleared).  Not sure if that matters, but the plan is to replace that drive as well later.

Since disk3 was part of the array, it has to be included in the array configuration or you have to set a new configuration.

 

Did disk3 have any data you wanted to keep?

Disk 3 did not have any data.  When the parity drive starting showing SMART errors, I pre-cleared Disk 3 to see if it would be a suitable replacement, which it appears to be (passed all SMART tests and the 3-day pre-clearing process).

 

I have 2 more drives waiting to be assigned, but I was going to add them to the array after replacing the parity drive.  Not sure if that helps, since selecting one of them from Unassigned Devices does not allow me to start the array.

 

If I set a new configuration, what will happen to the data on Disks 1 and 2?  Those have data that I do not want to lose.

You can add the new disks as part of New Config, rebuild parity, then format the new data disks. Existing disks will not be changed as long as you keep them assigned as they are.

 

It is very important that you don't accidentally assign any disk with your data to any parity slot or it will be overwritten by parity.

 

https://docs.unraid.net/unraid-os/manual/tools/#new-config

Thank you!  This did the trick, and parity is now being rebuilt.  I was also able to add the other two drives to the array.

 

For future users who might find this thread:  It will be helpful to write down the serial numbers of your disks that are holding data you do not want overwritten in the new config/parity process.  However, when I did this my existing data drives were not reassigned, so I didn't really need to do anything other than confirm the serial numbers matched.  Additionally, Unraid will tell you exactly which drives will be overwritten in red text next to the drive (in this case, it will be the parity drive(s)).