Parity | Data disk replacement help requested

Current array:

 

• 5 x 4tb disks (1 parity | 4 data)
• 1 nvme + 1 sata ssd cache pool
• 1 nvme unassigned device | boot disk for winVM

 

I am planning to replace all 5 platter disks in the array.  

 

 

New array:

• 1 x 12TB parity disk
• 4 x 10TB data disks
• 1 nvme + 1 sata ssd cache pool
• 1 nvme unassigned device | boot disk for winVM

 

However I do not have any available PCI lanes (for a riser card) nor any available ports to run preclear on a disk while the array is up.

 

The process I was planning:

 

1. stop array
2. uncheck start array on boot
3. power down
4. remove parity 4TB disk
5. add 10TB disk
6. boot unraid
7. preclear 10TB disk
8. repeat 1 - 7 for each of the data 10TB disks
9. repeat steps 1-7 for 12 TB parity disk
10. leave 12 tb parity disk in
11. boot unraid
12. assign 12 TB as parity
13. rebuild parity on array
14. once parity confirmed, replace each data disk (one at a time) rebuilding array progressively

 

Obviously pre-clearing 52TB of data will be brutally time consuming, leaving the array off-line for a week or two... but I do not see any other way while completely protecting my data and installing fault tested new spinners.

 

From what I understand is this the best practice?  Once Parity is rebuilt on 12tb Parity disk... can I use the array while rebuilding each data disk?

 

Thanks for any help!

 

Cheers.

 

EDIT:  would it be safe to use a usb 3.0 dock and desk fan?

Edited July 17, 20196 yr by J.Nerdy
usb 3.0 dock