Dual Parity Drive Swap

[Hawkins12]

Running Unraid 6.9.2 and had a question on the parity swap procedure.  Currently, I have dual parity drives in place -- 2 - 8tb drives.  I am looking to replace both of these to 14tb drives for future proofing, etc.  I was able to find the instructions at the link below however had a couple questions regarding the process as the process only addresses one parity drive swap and not a scenario where I already have dual parity

 

https://wiki.unraid.net/The_parity_swap_procedure

 

1) Are the instructions still valid for 6.9.2.  The concern I have is around the downtime of the array -- I assume will take 2 days as thats the length of my last parity check (8tb).  I'd like to avoid server downtime if possible and wasn't sure if there was a way to do this given I have dual parity

 

2) Are the procedures the same for each parity drive?  Do I do one first, then the other?  (means 4 days of total downtime potentially).

 

3) any tips or suggestions?

[JorgeB]

Parity swap is only needed when there's a disabled disk (or two with dual parity) and you want to use the current parity to replace that data disk, is that the case? You just mentioned upgrading parity.

[itimpi]

Why do you want to use the Parity Swap procedure?    If you simply want to upgrade both parity drives then stop the array: Unassigned the current parity drives; start the array to make Unraid ‘forget them’ stop the array; assign the new parity drives; start th3 array to start building the contents of the new parity drives.

 

the array remains available while building the new parity although performance is likely to be degraded.

 

you probably want to keep the old parity drives intact just in case a data drive fails while building the new parity as that gives you a recovery option.

[trurl]

1 minute ago, itimpi said:

you probably want to keep the old parity drives intact just in case a data drive fails while building the new parity as that gives you a recovery option.

Or just upgrade one at a time so you have one valid parity drive. If you write anything to the array while rebuilding parity the old parity disk is invalid.

[Hawkins12]

Thanks all for the comments.  Makes me feel better. 

30 minutes ago, trurl said:

Or just upgrade one at a time so you have one valid parity drive. If you write anything to the array while rebuilding parity the old parity disk is invalid.

I think I'll upgrade like this.  This seems to make most sense.  Eventually the 8tb will be redeployed as data disks but would be nice to have them as backup in case parity messes up

 

34 minutes ago, itimpi said:

Why do you want to use the Parity Swap procedure?    If you simply want to upgrade both parity drives then stop the array: Unassigned the current parity drives; start the array to make Unraid ‘forget them’ stop the array; assign the new parity drives; start th3 array to start building the contents of the new parity drives.

 

I think this is a case of bad terminology on my end.  I guess I thought I was doing a parity swap but really just upgrading.  I guess I confused what I wanted to do vs. what the instructions provided.  

 

Thanks all for your input!

[SudoPacman]

I'm doing the same once the preclear finishes on my two new 14Tb drives.

 

What did you go for in the end, swapping one or both?

If one which parity went first (I assume the second one)?

 

Cheers