Migrate from NAS320 2TB to NAS326 4TB

Neither will work. Unfortunately the NAS326 won't recognize a disk from the NSA320 and vice versa. However, when you're not afraid for the command line you can use an ssh shell to mount the '320 filesystem manually in the '326, and copy the content over.

I understand that if I mount a file system on '326 via ssh such as on
'320, then I have to move one of the disks back to '320 and the system
will clone it. Then I will return it to '326, I will also insert a
second empty disk and the system should clone itself.

'Clone' is not the word I would use here. You have to copy the files from one filesystem to another. But the filesystems and their partitions/raid array have to be created by the 326 and 320. The is no moment both disks are part of the same raid array.

But I would need instructions for each step.

Basically, when you have inserted the 320 disk in the 326, and the disk is sdb:

mdadm —assemble /dev/md3 /dev/sdb2 —run —readonly
mkdir /mnt/md3
mount /dev/md3 /mnt/md3
cd /mnt/md3
cp -a * /i-data/sysvol/admin

Copies everything to the admin share.

The strange characters before the run and readonly are a double minus. But this forum software exchanges that by something else, even in a code block.

The second option you mentioned is generally a better approach for migrating from your old NAS 320 to the new NAS 326 with larger drives. Here's a step-by-step guide for this approach:

1. Prepare the New NAS 326:
   • Insert one of the new 4TB drives into the NAS 326.
   • Initialize and set up the NAS 326 with the 4TB drive.
2. Clone Data from Old NAS 320:
   • Remove the 2TB drive from your old NAS 320.
   • Insert this 2TB drive into the NAS 326 alongside the 4TB drive.
   • Configure the NAS 326 to clone the data from the 2TB drive to the 4TB drive. This process may vary depending on your NAS's operating system, so consult your NAS documentation for specific instructions.
   • Wait for the cloning process to complete.
3. Expand the Partitions:
   • Once the cloning process is done, you should have a 4TB drive with a 2TB partition (the size of the original 2TB drive).
   • Use the NAS 326's disk management or storage expansion features to expand the partition to use the full 4TB capacity.
4. Insert the Second 4TB Drive:
   • After expanding the partition on the 4TB drive, insert the second 4TB drive into the NAS 326.
5. Set Up RAID 1:
   • Configure the NAS 326 to set up a RAID 1 array using the two 4TB drives. This will mirror your data for redundancy.
6. Data Verification:
   • Verify that all your data is accessible and properly mirrored on the new NAS 326.

Remember to back up important data before starting the migration process, as there is always a risk of data loss during hardware upgrades and configuration changes.