Replacing Parity and Disks - Fastest Option

[spamalam]

I have a fairly large array, it has a total of 180 TB, 2 parity disks and 20 array disks.  I have one spare slot in the hot swap bays.  My 4TB disks are approaching 6 years old so want to switch them, I've shucked a series of 18TB drives, and two have finished a pre-clear.  My parity is 14TB.  I use 114TB, with 66.4TB free.

 

New Disks:

5x 18TB

 

Parity:

2x 14TB

 

Disks to remove:

6x 4TB

 

I would like to:

Replace parity with 2x 18TB.

Replace 6x 4TB with 2x 14TB old parity drives.

Leave 3 hot swap 18tb to add to the array at later dates (I'm not going to have access to the hardware for a while and have enough space)

 

 

What's the fastest way to achieve this? 

 

I'm thinking of:

1. Use Unbalance to evacuate the 6x4TB with the array up.

2. Pre-clear 2x18tb.

3. Use "New Config" to then remove all the 4tb, replace the parity, and rebuild without trusting parity.  I understand this will effectively just make a filesystem from all the drives I choose and kick off a parity build as if it were new?

4. Wait for this to finish, stop the array, then add the two old parity drives to expand the array.

5. Re-run parity.

 

Can i eliminate 4+5?  I see the unassigned drives plugin can format disks.

 

This would risk me going without parity, I have however recently completed parity checks without issue and my last disk failure was one of these ageing 4TB, the rest are much more modern.

 

Edited August 9, 2021 by spamalam

[trurl]

3 hours ago, spamalam said:

make a filesystem from all the drives

I would quibble with your use of the word "filesystem" here but nevermind.

 

3 hours ago, spamalam said:

Can i eliminate 4+5?  I see the unassigned drives plugin can format disks.

Yes, just assign those old parity to data slots before building parity and you can format them in the array even before parity has finished building.

[spamalam]

Thanks this procedure worked great, I used unbalance to distribute data, I precleared the new parity disks, then I hit new config (you can put the disks in any order so i ordered them by disk slot), then removed the 6x 4TB, assigned the 14TB parity disks to data lots, 18TB to parity, reduced the number of drives down, hit start, acked i'd be rebuilding parity and hit format for the 14TB.  All well so far.