How to format more of 4TB drive as USB back-up

[bw37]

Model:  LS441de with 2 x 3TB Hitachi HGST drives in mirrored array
Firmware:  1.81-0.03

Using external USB drive to back up: Successfully formatted as EXT3 but "Unit capacity" is limited to 1664.7 GB
I did perform a successful backup, but hoped to have larger capacity available as server back-up grows.

Question:  How can I format the USB drive from the LS4441 (I assume) as EXT3 or XFS to better utilize the 4TB space?

Thanks for any suggestions.
PS:  Thanks to Buffalo for the improved USB drive recognition in 1.81! One problem I was having already solved.

[Eastmarch]

Needs to be formatted as a GPT partition. You almost certainly chose 'MBR'.

[bw37]

Eastmarch,
Thanks for the reply. I don't think that was it. I'm almost sure I checked the GPT box when I formatted it. I'll see if I can tell for sure either reading the drive information from the NAS or connecting it to my PC using a "Linux reader".

Hooked up directly to the PC, I could format it as one full capacity NTFS volume but I had reformatted into 2 "halves" to make it work with a router. I removed those volumes in Disk Management on the PC before reformatting it in the NAS. From looking over formatting issues on the forum maybe I also needed to "clean" it with Diskpart first. I think I'll use it as is for now and will get another drive to mess with so I have a backup. I think I'll get another drive to continue to experiment with. Eventually I'd like 2 backups anyway.

Related question:  Could I backup from the LS441 to a USB drive formatted NTFS? Reading through the many posts on older Buffalo units led me to believe that it needed to be EXT3 to use as a backup. But now that I can read them, all my other NTFS USB drives appear as folder "usbdisk1", same as the EXT3 drive and that seems all that is required for a backup destination.

Thanks for the help.

[Texturtle]

The newer units should work with NTFS, but I would still recommend using EXT3. And yes, you should do a diskpart clean on the drive before formatting it with the LS.

[bw37]

I thought I'd follow up just to confirm that doing a "clean" in diskpart solved my formatting problem.

I did get a second drive (a "bare" 4TB WD Blue). "Untouched" by a PC, it formatted fine as a single EXT3 partition (3697 GB) attached via USB to my LS441de.
Once I'd performed a back-up to the new drive, I "cleaned" the 4TB WD Green drive that I was discussing earlier in this thread. Once "cleaned", it also formatted as a single partition.

Thanks for the help!