Procedure to encrease volume space by replacing HHd with a bigger one

[antocara]

Hi,
I own F4-210 wih 4 Hdd (8tb, 8tb, 4tb and 2tb). The Hdd are formatted as ext4 and each configurated as indipendend single volume device.
I'd like to increase the available space by substituing the 4tb and the 2tb Hdds with two 8tb ones.

What I would do is:

1) backup all the data stored in the 4tb and 2tb hdds
2) remove the 4tb and 2tb and replace them with 2 8tb hdd
3) Format them as ext4 and configure the two new Hdd as two single volume storage one.
4) Copy all the backed up data back to the new volumes

Is this right ? If not please tell me what is the right procedure.

Also I'd like to know if there are faster procedure that I can apply. As an example I have a linux PC with debian distro.
I woult attach the old and the new hdd into my debian pc at the same time. I will do that after step 3 of the above procedure so that I have the 2 sistem partitions and data partion in place on the new hdd.
I'd like to copy directly the data stored in the partition data of the old hdd to the new one. To do that Ineed to mount the two vgx-lgx partition on my debian pc. Since I' not a linux raid expert, I need the step by step command line procedure to properly mount the partitions do that data will be accessed in my linux pc so that I can use a simple "cp -af /mnt/d-old/* /mnt/d-new commad to copy the data. d-old and d-new are respectively the old and the new mounted data partitions on my debian pc.

Alternately (even better) how can I clone direcly all the partitions from old hdd to the new one using my debian pc ?
In this case I'll complete only step 1) and then attach the old and the new hdd on my pc. Please tell me a step by step procedure to do so.
Also I need to a step by step command line procedure to correclty resize the data partition on the new hdd.
I know that I can use gparted to simplify the task, but I notice also that gparted had some difficulties in handling in the right way raid partitions.

I'm sorry to be so long and maybe imprecise in my request due to lack of knoledge in linux and in Raid cofigurations.

Help will be very much appreciated and I believe could be useful for many other user.

[TMSupport]

1. Pull out an old hard disk and insert a new hard disk, create storage pools and volumes on the new hard disk.
2. log in to the SSH terminal.
3. Use the cp command to copy data.
4. After the copy is complete, unplug the two hard drives and insert the other two.