Question Linux external drive mount mystery ("not a block device") ?

[sheremey2]

[ I did an extensive web search before posting here; Linux experts, show yourself! ]

For some reason, a system ( Ubuntu 20.04.4 LTS) that worked with my external drives, went crazy and now returns '/dev/sdb1 is not a block device' error following any mount attempt... Puzzled.
The 'dmesg' output clearly shows that the disk is visible to the system and is assigned sdb: sdb1 Still, a mount attempt returns "not a block device" thing...


[ 2938.108348] usb-storage 2-4:1.0: USB Mass Storage device detected
[ 2938.108567] usb-storage 2-4:1.0: Quirks match for vid 174c pid 55aa: 400000
[ 2938.108674] scsi host6: usb-storage 2-4:1.0
[ 2956.544265] scsi 6:0:0:0: Direct-Access WDC WD80 EFZX-68UW8N0 83.H PQ: 0 ANSI: 5
[ 2956.544834] sd 6:0:0:0: Attached scsi generic sg1 type 0
[ 2956.545173] sd 6:0:0:0: [sdb] 15628053168 512-byte logical blocks: (8.00 TB/7.28 TiB)
[ 2956.545463] sd 6:0:0:0: [sdb] Write Protect is off
[ 2956.545469] sd 6:0:0:0: [sdb] Mode Sense: 43 00 00 00
[ 2956.545753] sd 6:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 2956.606388] sdb: sdb1
[ 2956.607581] sd 6:0:0:0: [sdb] Attached SCSI disk
(base) om@DL:/mnt/media$ sudo mount /dev/sdb1 /mnt/media/usb
mount: /mnt/media/usb: /dev/sdb1 is not a block device.


fdisk output:


Disk /dev/sdb: 7.28 TiB, 8001563222016 bytes, 15628053168 sectors
Disk model: EFZX-68UW8N0
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: XXXX (censored)

Device Start End Sectors Size Type
/dev/sdb1 2048 15628053134 15628051087 7.3T Linux filesystem


The funniest part is that lsblk output (below) lists this as a block device! So, it is a block device, but when you try to mount it, it is suddenly not...


sdb 8:16 0 7.3T 0 disk
└─sdb1 8:17 0 7.3T 0 part

• And I did not change anything in the system between the time when mounting worked just fine and now...
• Also, the same disks (I checked 3 of them, all worked with this very system before) now return this error!
• There are no entries for sdb in fstab

Any wise advice? Thank you!

 

[palladin9479]

That error usually means you are missing the package that supports that file system, or the file system is a format that the package doesn't recognize.

mount -t <fs type> <device> <mount location>

 

[Grobe]

What happens if you boot from a Live desktop (iso file) - and then try to insert the external hdd ?

 

[sheremey2]

That error usually means you are missing the package that supports that file system, or the file system is a format that the package doesn't recognize.

mount -t <fs type> <device> <mount location>

Thank you for the hint!
Indeed, all I needed to do is run sudo modprobe ntfs
After that, mounting worked like charm...
Why the ntfs package (apparently existing and working before that) suddenly dissolved in the air, is still a mystery ))

Thanks!

 

[sheremey2]

What happens if you boot from a Live desktop (iso file) - and then try to insert the external hdd ?

Thanks, that makes sense. However, I fixed the issue a few minutes before getting your suggestion (above). Thanks!

 

[palladin9479]

Thank you for the hint!
Indeed, all I needed to do is run sudo modprobe ntfs
After that, mounting worked like charm...
Why the ntfs package (apparently existing and working before that) suddenly dissolved in the air, is still a mystery ))

Thanks!

Looks like the package was installed but the kernel driver was not loaded, which is weird possible if booting from something like an ISO. Packages are usually installed with a package manager like yum, dnf or apt while kernel drivers are loaded with something like modprobe or through the boot config.