I want to move some data around the array and remove a couple of disks. I would like to do it with only one parity rebuild if possible.

Here's my current layout:

I have a single share with two disks called Backup1. I contains only data that is in other shares on the array. I only have one server so to "backup" data that I can otherwise not duplicate, I "back it up" onto another share that only contains that type of data. That is, the share consists of 2 disks that are assigned only to that share. I know, this is not a real backup but I arrived at this solution because it seems to me that backing up this data onto, say, an external attached disk would actually be less safe because there would be no parity so why not put those disks into the array?

Anyway, there are currently 2 disks in this dedicated Backup1 share. I want to remove both disks from the array. One of the disks I will simply remove and put in cold storage. The other I need to copy the data onto another disk so as to retain the backup data and then I want to remove it too from the array.

Here is the current setup:

Backup1 share:

7.3 TB disk1 current has 6.6 TB allocated

7.3 TB disk3 currently has 6.8 TB allocated

other disks:

9.1TB disk4 currently has 8.2TB allocated

13TB disk10 currently has 40GB allocated

My plan is to move all the data from disk4 to disk10 leaving disk4 empty

then move all data from disk1 to disk4 this would become the only disk in Backup1 share

then remove disk1 and disk3. disk3 would go into cold storage. disk1 would become a new unassigned disk used to do incremental backups of other data (movies) for eventual removal to cold storage.

My question is: what procedure will result in only one "new config" and thus parity rebuild?

Thanks for any help.

If you are going to remove both disks at once, you only need to rebuild parity after they are removed.