Replace JBOD in PR4100 with larger size

I have PR4100 with 2 6TB drives and 2 empty slots. Drives are NOT RAID! Both set as JBOD. I would like to replace the 6TB drives (one at a time) with 10TB and copy structure and files from existing drive to new drive.

I find the manual confusing. Can someone guide me before I make a mess?

I suppose I could install new 10TB drive, create structure and then copy files from Public_1 to Public_3. A lot of network traffic that way! Is there an internal method?

You can easily install a 10TB disk and copy files from one of the 6TB disks. Expect the copy process to be sluggish but eventually the data will be done. You can migrate data from both 6TB disks if they are not full to a 10TB disk.