[SOLVED] Parity Swap Procedure - Asking to Copy Again

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I have been following the Parity Swap Procedure here (https://wiki.unraid.net/The_parity_swap_procedure) and got to Step 14, I have let it copy the data from the old Parity drive to the new one and it completed fine.


I came back to it after it completed and it was prompting for the password to start the array (and subsequently start the rebuild of data from parity), I was about to enter it but accidentally refreshed the page, now its asking me to do the whole parity copy again (both drives show a blue icon and say New Device).


How do I get it back to the previous state where it knows that the new Drive has had the Parity copied to it, so I dont have to spend another 30+ hours letting it copy over, and that the drive it was swapped with needs rebuilding when the array starts?



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Parity swap procedure needs to be done from start to finish, any other step/interruption will make it stat over, if you're absolutely sure the parity copy completed you could use the invalid slot command, but I would advise just starting over, also 30+ hours is a lot, unless the parity is very large.

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Thanks for that.


The Original Parity was 10TB and its been replaced with a 14TB drive, which could be some reason for the 30+ hours.


Surely, as everything has been copied over and the array has not been able to be started since, there must be some way to "force" it back into the state, as all the data is still there and nothing has changed, its just the unRAID GUI being restrictive.


Are you able to provide some info on the Invalid Slot Command please, I might give that a go if I dont get any other results.

Edited by timethrow
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This will only work if the copy was completed.


This assumes you're running a recent version of Unraid, it might not work on very old releases, it works on any release newer than v6.2, it also assumes you have single parity, if you have dual parity the command is different (remove the 29)


-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all assignments and assign any missing disk(s) if needed, make sure new parity is assigned to the parity slot and old parity assigned to the disk to be rebuilt
-Important - After checking the assignments leave the browser on that page, the "Main" page.

-Open an SSH session/use the console and type (don't copy/paste directly from the forum, as sometimes it can insert extra characters):


mdcmd set invalidslot # 29

Replace # with the disk number you want to rebuild, i.e. to rebuild disk3 it would be:

mdcmd set invalidslot 3 29


-Back on the GUI and without refreshing the page, just start the array, do not check the "parity is already valid" box (GUI will still show that data on parity disk(s) will be overwritten, this is normal as it doesn't account for the invalid slot command, but they won't be as long as the procedure was correctly done), disk# will start rebuilding, disk should mount immediately but if it's unmountable don't format, wait for the rebuild to finish and then run a filesystem check

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  • JorgeB changed the title to [SOLVED] Parity Swap Procedure - Asking to Copy Again

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