I'm trying to mount an external brand new 3 TB MyDrive HP USB device on a brand new 2011UiAS-2HnD with (updated) current Firmware 3.19 and RouterOS 6.22.

First Problem: When just attaching (not yet mounting) the device I constantly see just a fraction 746.5 GiB of the disk's 3 TB inside the Web frontend.

Test 1: Formatting as Fat32 using the router's Web GUI. Formatting claims to succeed but mounting fails. When I attach the RouterOS formatted disk to my Linux Box (current Ubuntu 14.04 LTS 64 BIT) mounting fails as well with the following /var/log/syslog message: mkfs.vfat on my Linux box tells me that the minimum logical sector size for this USB device is 4096.

Test 2: Formatting as ext3 on router: This works but leaves me with the previously noted limit of 746.5GIB ( ~25% usable space, not too impressive).

Test 3: Formatting on my linux Box using mkfs.ext3. I can mount the device on Linux and "df -h" shows the expected full 3TB capacity. Mounting the device on RouterOS however fails.

Test 4: Formatting the disk on my Linux box using FAT32 works + mount works. Mounting on RouterOS fails.