USB Hard Drive larger than 2TB on non-UEFI?

Is this possible? If not, I’ll use 2TB USB drives. I don’t want to build a new system, or even replace the motherboard. I just want to free up space on the internal hard drive, lots of video stuff!

I don’t really know, and it probably depends on the BIOS.

With a reasonably new BIOS, I would guess it is okay provided:

You use a GPT partition table.
The partition containing “/boot” is in the first 2T of space on the disk.

My motherboard has an older BIOS, not sure, but I don’t think it does GPT? Anyway, I won’t be booting from the USB drive, it’ll just be for my data files - video stuff, in particular.

That doesn’t actually matter. GPT partitioning does have a protective MBR. And as long as the BIOS treats that as it would any other MBR, it should be fine. The boot code in the protective MBR needs to know about GPT, but the BIOS doesn’t. The main problem will be that BIOS calls cannot read all the way to the end of a large drive. As long as that isn’t needed during booting, it should be fine.

Anyway, I won’t be booting from the USB drive, it’ll just be for my data files - video stuff, in particular.

That makes it even more likely that it will work. But you won’t really know until you try.

I have a few hard drives > 2TB but I confess I have only used them with UEFI laptop and desktop.

I note this thread: Trying to understand linux support for 4TB hard disk drive on legacy BIOS where it suggests (as stated above) it really depends on the BIOS or the external HD itself.

Nominally MBR will not support > 2TB so one needs GPT for some old PCs. But many external disks and a few internal disks now use 4 KiB (4096-byte) logical sectors, though, which raises the MBR limit to 16 TiB.

This part of the linked page seems to say a 4GB data drive will work:

All that said, since the new disk is a non-boot disk, you needn't really  be concerned with these issues. You can boot Linux in BIOS mode from an  MBR-partitioned SSD and use the GPT-partitioned 4 TiB hard disk for  data storage without problems. If your needs change in the future, you  might need to re-evaluate the configuration, but I wouldn't worry about  it now.

The USB hard drives come formatted with NTFS, I never reformatted any of my 2TB drives. Am I correct in assuming a 4GB drive will be GPT partitioned?

When I bought a 4 T WD40EZRX-22SPEB0 it had gpt. With my new machine I continued using bios/mbr because it worked. But finally I wished I had switched to uefi/gpt when assembling the machine.

I have 4 tb USB attached to old machines (over 15 years old) with msdos partition tables - all formatted with gparted to ext4 with no issues.

The drive is on order, I’ll try to remember to report back with my results. Thanks to all who replied!

The drive arrived today, so I booted up GParted Live CD, the version for my non-UEFI “BIOS” machine. I deleted the existing partition, then created a new GPT partition, created the primary partiton, and formatted it for ext4. When I tried to create a directory in Dolphin, that option was greyed-out. So I checked the permissions, and it said “root”. Then I opened the “superuser” version of Dolphin, and changed the permissions to my user name for “user”, and the “Group” to users. It works now, but the drive activity LED never stops flashing. Did I do something wrong? I haven’t tried this drive on my laptop yet, hoping it works on that too… Other than the constantly flashing LED, it seems to work.

I have a flash drive with an LED. And that LED is always flashing when it is plugged in.

On the other hand, I have a hard drive in an enclosure, and the LED there only flashes when there is read/write/seek activity.

The flashing might not be for anything important.

My 2TB USB drives don’t do that, but I left them as-is, formatted with NTFS, not sure if that has anything to do with it. No biggie, it’s working so far, only wanted it to offload my large collection of DVD & Bluray rips, running out of space on my PC. The drive showed 3.58TiB in Dolphin before I started copying stuff to it, should be ok. Just tried it on my laptop, works fine, though that has the same user name, so no idea about that weird permissions thing. But it works for the intended use, I’m happy.

My 4 TB drive(s) have a steady blue light when power applied, and flash when access taking place. I also left them formatted NTFS (so I have compatibility with my wife and colleagues PCs for file transfer (private home videos) and also backup’s of wife’s data from an MS-Windows PC)

All of my external drives have less than 4 TB, but their behavior is the same.

My 2 TB drives are the same, too. This 4 TB unit is the only one that always flashes, just a little less often with no files being transferred or accessed. It seems to work ok, though. I’m still copying files to it, about 900 GiB left. It’s only for playing videos, not a critical backup drive, so I’m not worried. It’s just weird.