I am trying to read the content of a 1Tb external disk. The device was part of an external nas (dlink 320) using raid 1.

when I plug the hard disk using the usb port no partition is mounted. The output of fdisk

userk@norAdrenaline:~/$ sudo fdisk -l /dev/sdf
GPT PMBR size mismatch (1953525167 != 244190623) will be corrected by w(rite).
Disk /dev/sdf: 931,5 GiB, 1000204795904 bytes, 244190624 sectors
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/sdf1           1 1953525167 1953525167  7,3T ee GPT

The output of gdisk is:

userk@norAdrenaline:~/$ sudo gdisk -l /dev/sdf
GPT fdisk (gdisk) version 1.0.1

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: not present

Creating new GPT entries.
Disk /dev/sdf: 244190624 sectors, 931.5 GiB
Logical sector size: 4096 bytes
Disk identifier (GUID): 95DF7C2D-BDB1-4AA8-8D2A-53DC61FF06E6
Partition table holds up to 128 entries
First usable sector is 6, last usable sector is 244190618
Partitions will be aligned on 256-sector boundaries
Total free space is 244190613 sectors (931.5 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name

When I try to mount the disk I get

sudo mount /dev/sdf /mnt/stora
mount: /dev/sdf is write-protected, mounting read-only
NTFS signature is missing.
Failed to mount '/dev/sdf': Invalid argument
The device '/dev/sdf' doesn't seem to have a valid NTFS.
Maybe the wrong device is used? Or the whole disk instead of a
partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?

How can I mount and read the content of the hard disk?


  • Thanks, mdadm doesn't recognize the disk

    userk@norAdrenaline:~$ sudo mdadm --examine /dev/sdf1
    mdadm: cannot open /dev/sdf1: No such file or directory
  • @Johan Myréen The hard disk is connected to the pc using an external drive enclosure using an usb to sata proprietary adapter

  • The point is that often the RAID structure is often written in the first sector(s). Try to find a valid partition table ahead, and see what you can make of it. Apr 8 '18 at 16:38
  • 1
    I see the USB interface reports that the disk has 4k sectors, both logical and physical. This is unusual, since disks usually still use sector sizes of 512 bytes, at least for the logical sector size. This makes me suspect the USB interface is playing games with the sector size, as described in the accepted answer to this Superuser question. How did you connect the drive to USB? Apr 8 '18 at 16:44
  • 1
    Trying to mount /dev/sdf doesn't make any sense if there is a partition table. You would have to mount /dev/sdf1 instead. But that may not work either. What is the output of mdadm --examine /dev/sdf1? Edit your question and add it there. Apr 8 '18 at 16:46
  • 2
    If I had this problem, I would try connecting the drive directly using its native interface (SATA) and see if the problem persists. By the way, Rod Smith who provided the answer I linked to above really knows what he is talking about when it comes to disks and partitioning. He's the author of the *gdisk GPT partitioning programs. Apr 8 '18 at 17:09
  • 1
    My first approach would also be to use the original enclosure/controller... I just assumed that if the OP is not using it, it is because it is dead. Apr 8 '18 at 17:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.