Just got one of these hoping to see close to 4TB. The device has different RAID Modes, 1, 0, "two disks", and then "Spanning".

Spanning is supposed to "combine" the two drives into one (striping?)

When I put it in this mode, Linux (Redhat 5.4) only sees 1.8 TB. If I do the two disk mode, it sees two 2 TB drives.

Anyone know if there is anything I can do to see the 4TBs?

Regular partition tables using LBA cannot deal with volumes >2TB. Use a GPT partition table.

I tried parted but that also balked when I tried to make anything greater than 2 TB

In parted, did you do a 'mklabel gpt' first?

Post the model number of drive station and the size of your hard drive(s).
The largest hard drive listed for the HD-WLU3R1 is 3TB. If you have a single 4TB hard drive then it may not be possible to see the full disk zize. Changing to a GPT partition will probably not fix the problem due to the hardware limitations.

I did do a mklabel gpt first.

The model indicated on the case is HD-WL4TU3R1. Interestingly, the model reported in dmesg is the one you indicated.

I called their support but they claimed the S/N: on the bottom was impossible, then played the "we don't support linux card" without so much as sparking a neuron on the issue.

Unless there is some special driver that helps windows and MACs see 4TB on this device, I don't understand why linux couldn't read it correctly.

When I put it in "normal" mode, it shows up as two drives:

dmesg:

usb-storage: device found at 11
usb-storage: waiting for device to settle before scanning
usb 1-3.1: reset high speed USB device using ehci_hcd and address 11
Vendor: BUFFALO Model: HD-WLU3/R1 1 Rev: 0001
Type: Direct-Access ANSI SCSI revision: 06
SCSI device sds: 3906250992 512-byte hdwr sectors (2000001 MB)
sds: Write Protect is off
sds: Mode Sense: 1f 00 00 08
sds: assuming drive cache: write through
SCSI device sds: 3906250992 512-byte hdwr sectors (2000001 MB)
sds: Write Protect is off
sds: Mode Sense: 1f 00 00 08
sds: assuming drive cache: write through
sds: unknown partition table
sd 12:0:0:0: Attached scsi disk sds
sd 12:0:0:0: Attached scsi generic sg20 type 0
Info:emcp:Received add upcall for index 0x12 devno 0x4100020
Vendor: BUFFALO Model: HD-WLU3/R1 2 Rev: 0001
Type: Direct-Access ANSI SCSI revision: 06
SCSI device sdt: 3906250992 512-byte hdwr sectors (2000001 MB)
sdt: Write Protect is off
sdt: Mode Sense: 1f 00 00 08
sdt: assuming drive cache: write through
SCSI device sdt: 3906250992 512-byte hdwr sectors (2000001 MB)
sdt: Write Protect is off
sdt: Mode Sense: 1f 00 00 08
sdt: assuming drive cache: write through
sdt: unknown partition table
sd 12:0:0:1: Attached scsi disk sdt
sd 12:0:0:1: Attached scsi generic sg21 type 0
Info:emcp:Received add upcall for index 0x13 devno 0x4100030
usb-storage: device scan complete

What are the sizes of the hard drives?
So you are saying that Windows and Macs see the entire 4TB but RH does not.

It appears I was reading more into the problem than what was actually presented.

They are 2 TB drives. Allegedly windows and macs are able to see 4TB in what they call "spanning mode". I don't have a windows or mac system around to test it on.

so the [bert] eyes have it. Buffalo DriveStations do not play nice with Linux. If you're looking for 4TB, it's not here.

This sounds like the support for different modes are in the driver which you have to install on Windows resp. Mac OS X. When I check their documentation, there is no switch at the device where you can select the desired mode?