Hi All,
I have a 4TB drive that was originally in a PC connected via SATA. I now wish to put it in an external enclosure and connect it via USB, however this is proving more difficult than I expected, and from what I understand itâs Windows XPâs fault.
On attempting to mount the drive with sudo mount /dev/sdc /mnt, I receive the following error:
mount: /mnt: wrong fs type, bad option, bad superblock on /dev/sdc, missing codepage or helper program, or other error.
The output of fdisk -l is as follows:
Disk /dev/sdc: 3.64 TiB, 4000787025920 bytes, 976754645 sectors
Disk model: Expansion Desk
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x00000000
Device Boot Start End Sectors Size Id Type
/dev/sdc1 1 4294967295 4294967295 16T ee GPT
As can be seen, the disk is detected correctly as a 3.64TiB drive, but there is a partition thatâs read as 16TB. This, AFAIK, is because the sectors are incorrectly read as 4096 bytes long when they should be 512 bytes, and this is a thing that external enclosures do to ensure MBR compatibility with Windows XP.
I tried overcoming this by mounting as follows:
$ sudo mount -o ro,offset=$((1*512)) /dev/sdc1 /mnt
however now I have a new error:
mount: /mnt: failed to setup loop device for /dev/sdc1.
Trying to mount with sudo mount /dev/sdc1 /mnt only yields
mount: /mnt: special device /dev/sdc1 does not exist.
Iâm at a loss as to how to mount this drive - at least, without reformatting it. Is it at all possible? Once Iâve cracked the code, can I configure /etc/fstab to do it automatically for me, or am I stuck in this limbo-land where I have data on my disk thatâs only readable with a hacky workaround? As a last resort, I think I can plug it back in via SATA, copy all 4TB off, plug it in via USB, reformat it and copy everything back on, but I want to avoid that hassle.
Edit: Output of fdisk -l when connected via SATA. Note the sector size is now 512 and the drive mounts happily.
Disk /dev/sdb: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: HGST HDN724040AL
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 5852E3A7-A2E4-4589-9D93-F8020C2D7E54
Device Start End Sectors Size Type
/dev/sdb1 2048 7814035455 7814033408 3.7T Linux filesystem
Your fdisk output shows a single partition of type ee which according to https://en.wikipedia.org/wiki/GUID_Partition_Table is the type for the protective MBR partition shown by MBR tools when looking at GPT partition tables.
Try using gdisk -l instead of show the GPT partition table.
i have a some sata->usb adapters/enclosures/docks that canât be used with > 2tb drives or with 4Kn (native 4k sectors, no 512 emulation) drives. i also have a 2-bay cheap nas that can only do 2x1tb or smaller and thereâs no new firmware or hacks to âfixâ it even though itâs linux under-the-hood.
start with hooking it back up to sata to copy anything on it you want elsewhere, check the filesystem, and run the extended diagnostics.
This is the most likely problem. There is no way the output from fdisk should be different between the two connections (the USB and SATA) if they are both working correctly.
Commenting because id also like to know.
In my case I resorted to using another enclosure/ adapter
The only enclosure I have that works out of the box is one of those âSATA to USB adaptorsâ rather than a bona fide â3.5 inch drive enclosureâ. Itâs not ideal for long-term use.
I wonder if thereâs a place to find out if any given make/model of enclosure will report the sector size as 512 bytes. Then, presumably, one could purchase an enclosure off that list and be confident the disk will be readable.
I dont know either. I used a seagate usb to sata adapter too and that gave me problems with large drives. Nothing on the datasheet mentioned anything, so i had an old backup external drive and swapped the drives to do my formatting/ transfer before putting the original back together
I have no experience in this specific matter, but you could look up how to switch the sector size from 512 bytes to 4096 and, you know, just do the opposite.
