I looked for info on rebuilding a RAID 10 to a larger capacity and found ZERO posts or any helpful support (except to say adding capacity options do NOT support RAID10). So I’m posting my successful experience so the next person searching will find something useful.
Background: I had a EX4 that was useful for storing my documents. I had enough good experiences that I got an EX4100 when I needed storage for RAW DSLR photos (I am a photographer with Nikon D750 and D850 taking thousands of images). When OS5 came out and it didn’t work with EX4, I replaced it with a refurbished EX4100.
My first EX4100 had 4x 3TB WD red disks. One drive started to have some SMART indicators going south, so I looked for replacements. With Presidents’ Day sales, I went with 8TB Red disks. I decided to go ahead and replace all the disks with these 8TB. So I got 5x 8TB to have a spare in case of disk failure.
Given that I have RAID 10, this means backing up the data externally and then reformatting/rebuilding the RAID 10, then restoring the data from external backup. Fortunately I had a Sabrent USB external drive housing that I could use with the “spare” 8TB drive. I also had a MyPassport 5TB SSD for photography on trips, and I had recently cleaned it off. So two external methods of backing up my current RAID volume.
First, I took out a single 3TB drive and replaced it with 8TB drive and let the RAID rebuild. I repeated for the other 3TB drives. So then I had the EX4100 with 4x8TB drives, but still running as if a 6TB capacity mirrored RAID 10. And the RAID10 offers no method for easily expanding. So after replacing the physical drives, I then used Acronis TrueImage to backup AND validate all the RAID10 shares to my external drives. This gave me TWO separate backups (my original 4x3TB drives were still able to run and were intact (and labeled to put them back correctly) in case of catastrophe. AND I had the Acronis TrueImage backup to my external USB drive. Finally, I logged into the EX4100 as ADMIN and did a configuration backup and saved it on an external drive–just in case something went wrong.
So then, the moment of truth: login to EX4100 as admin and choose “Settings” and then “Configure RAID Mode”. For whatever reason, there is no obvious interface directions to explain this, but you choose to “Configure RAID” as “RAID 10”. Which seems stupid, since it is ALREADY RAID 10. But this then prompts you on which disks (correctly recognizing the larger physical sizes) and if you want to use all of the physical capacity for the new RAID 10 Array. Once you configure that, it THEN warns you that all data in the current configuration will be deleted. So you hit “OK” and it builds the new 4x8TB disks into a 16TB capacity striped array on 2 disks and then mirrors that on the other 2 disks to complete the RAID10 array.
FINALLY, I could recreate the original Shares and then use Acronis TrueImage with the external drive to restore the files.
This took me about a week because I’m careful and risk averse. I could have backed up the array, pulled the four old 3TB drives, then loaded the four new 8TB drives, then restored the shares and the data. I decided to add the 8TB disks, one by one to confirm each worked and allow me to have the EXTRA backup of a complete set of four 3TB disks with the original array. Then I backed up the data WITH validation (taking another 2 days for the 3.5TB of data on the original array). Finally, I rebuilt the new, higher capacity array, and then restored the data over another 2 days.
It can be done quicker and more subject to risk. It is a pain, in any case. But it can be done. Perhaps this post will save someone some searching and angst and give them a positive, confirmed success story.
Best to you.