I have an external drive with an ext4 partition /dev/sda1 I use for my local borg backups.

It is simply plugged in via usb port, and, mounted with an fstab generated systemd automount entry. I ran a backup yesterday in the evening without any errors, and this morning, I plugged it in, it was not recognized anymore. The drive would show up with lsblk, but no partition under it.

I ran sudo fsck -R -C -V -t ext4 /dev/sda1 and got the following output:

fsck from util-linux 2.39.2
[/usr/bin/fsck.ext4 (1) -- /dev/sda1] fsck.ext4 -C0 /dev/sda1 
e2fsck 1.47.0 (5-Feb-2023)
fsck.ext4: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda1
Could this be a zero-length partition?
/dev/sda1: status 8, rss 3232, real 0.002321, user 0.001784, sys 0.000000

I have no idea how to interpret that. I only can see the exit code status 8 the man page describes as an 'operational error'.


Output for sudo parted /dev/sda print

Error: Invalid partition table on /dev/sda -- wrong signature 0.
Ignore/Cancel? I                                                          
Model: SABRENT  (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type      File system  Flags
 1      8225kB  1000GB  1000GB  extended               lba

Output of sudo dmesg right after plugging the drive in

[16265.871467] usb 2-6.4: new SuperSpeed USB device number 15 using xhci_hcd
[16265.889474] usb 2-6.4: New USB device found, idVendor=152d, idProduct=1561, bcdDevice= 2.04
[16265.889486] usb 2-6.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[16265.889491] usb 2-6.4: Product: SABRENT
[16265.889495] usb 2-6.4: Manufacturer: SABRENT
[16265.889499] usb 2-6.4: SerialNumber: DB9876543214E
[16265.899660] scsi host4: uas
[16265.900160] scsi 4:0:0:0: Direct-Access     SABRENT                   0204 PQ: 0 ANSI: 6
[16268.706521] sd 4:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB)
[16268.706530] sd 4:0:0:0: [sda] 4096-byte physical blocks
[16268.706759] sd 4:0:0:0: [sda] Write Protect is off
[16268.706768] sd 4:0:0:0: [sda] Mode Sense: 53 00 00 08
[16268.707113] sd 4:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[16268.707265] sd 4:0:0:0: [sda] Preferred minimum I/O size 4096 bytes
[16268.707270] sd 4:0:0:0: [sda] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
[16268.724287]  sda: sda1 < >
[16268.724396] sd 4:0:0:0: [sda] Attached SCSI disk
[16296.811964] usb 2-6.3: reset SuperSpeed USB device number 14 using xhci_hcd
[16340.865861]  sda: sda1 < >

Following telecoM advice, I ran sudo losetup --sector-size 4096 -P -f /dev/sdx. I have a loop1p1 device/partition now.

❯ sudo parted /dev/loop1p1 print
Error: /dev/loop1p1: unrecognised disk label
Model: Unknown (unknown)                                                  
Disk /dev/loop1p1: 4096B
Sector size (logical/physical): 4096B/4096B
Partition Table: unknown
Disk Flags: 

❯ sudo fsck.ext4 -f /dev/loop1p1
e2fsck 1.47.0 (5-Feb-2023)
ext2fs_open2: Bad magic number in super-block
fsck.ext4: Superblock invalid, trying backup blocks...
fsck.ext4: Bad magic number in super-block while trying to open /dev/loop1p1

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
    e2fsck -b 32768 <device>


Should I give up on trying to recover this partition ? (I have redundant backups, it is not a catastrophe for me, I just want to learn in anticipation for the day it might be one).

Thanks in advance for your help.

  • Your first assumption is interesting because the drive is a SATA disk for which I bought a case recently (as shown in my edit, the manufacturer is sabrent). Maybe I went too cheap with that enclosing. Anyway I tried getting the sata drive out and back in, with no effects. I added the info you requested, by could not find /var/log/kern.log. I am on manjaro kde if that helps. thanks for the reply anyway.
    – lyndhurst
    Sep 8, 2023 at 12:05
  • You are right, I did not think of looking for it this way. I am not going to insist then, I am going to get a new case and research the manufacturer more carefully this time. I would mark your first comment as an answer and 'close' this question, but I am not sure how to proceed. Should I answer my own question ?
    – lyndhurst
    Sep 8, 2023 at 12:57
  • 1
    Note Sector size (logical/physical): 512B/4096B. If the case originally used native 4KiB sectors, you might need losetup --sector-size 4096 -P -f /dev/sda and then access the whole disk via /dev/loopN and its partitions via /dev/loopNpM (where N is the first free loop device number and M is a partition number).
    – telcoM
    Sep 8, 2023 at 13:16
  • 2
    Editing the original question is exactly the right way to add more information to a question on StackExchange. But although the fsck response is different, it is unfortunately not any better; in fact, it looks like the fsck on sda1 got slightly further before giving up. I would agree with @roaima's estimation at this point: the Sabrent case is probably failing. (BTW, when using a loop device, you should use parted /dev/loop0: directing parted to the loop0p1 partition device will not yield any useful information unless the partition is used as a disk image for a VM.)
    – telcoM
    Sep 8, 2023 at 18:12
  • 1
    Product: SABRENT - enough said. 90% of Sabrent USB/SATA adapters are Hot Garbage™ Sep 9, 2023 at 0:35

1 Answer 1


My first assumption would be a faulty case, particularly as you've got pluggable USB involved. Check that it's plugged in properly (both ends of the cable) and there's sufficient power.

I would also check the partition table, which you added to your question. Unfortunately it too shows a faulty read from the device, which is why I suspect the hardware.

Sadly, there are lots of "it doesn't work" posts with the particular vendor id (0x152d) and the product id (0x1561) that you showed. As an example I searched Google for "linux sabrent 152d 1561 usb". You might be better with a different case (I've found no issues with my RSHTECH 3.5in SATA case, but as they're all built to low budgets my experience suggests it's often a matter of potluck.)

  • thanks again for the swift reply, I think you were right from the start. Lesson learnt about cheap connectors between quality devices, an obvious weakest link analogy when you think about it.
    – lyndhurst
    Sep 9, 2023 at 6:27

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