I have been running two standard Toshiba 3 TB hard drives as data drives on my Linux (Slackware) server with one backing up to the other twice a day with rsync. One of them failed after only 12 months in service so I decided to buy two 4TB long life HGST Deskstar NAS drives thinking they would (hopefully) reduce the risk of another hard drive failure as well as increase my storage capacity. Unfortunately I have run into a snag. I have installed both new NAS drives but I cannot make Linux recognize more than 2 TB on each drive even though fdisk indicates I created a 4 TB primary partition. Since the 3 TB drive is recognized when it is mounted, it does not appear to be the 2 TB limit imposed by some of the older kernels.

Since I could not make one large partition I figured a solution that might work, even if not the best solution, would be to make two 2 TB partitions using fdisk. Much to my dismay however I found that Linux would not recognize the second partition so as of now I have no way of using the full 4 TB.

I read the directions that came with the new drive and although you have to use special software (HGST GPT Disk Manager) with Windows, it says that no "HGST Edition GPT Loader" is required with Linux or Mac OS.

I found a lot on the web about using external NAS storage drives amd building a NAS server with Linux but very little about using internal NAS drives as you would a normal hard drive. Is there something that makes these drives different from normal drives that I am not aware of? I am going to keep looking and trying different things but if anyone recognizes what the problem might be and can offer a solution or even a possible solution that I can try, I would be grateful. Thanks

Disregard. I really was not thinking. While I was waiting for the moderator to release my post I kept on searching the web and parrted was the answer instead of fdisk. df now reports 3.8TB free space on the new drive. I must have used that on the 3 TB drive as well earlier after going through this same exercise and unfortunately it did not stick in my memory. Perhaps it will this time. Sorry I bothered you.