[SOLVED] Cannot access GPT disk through USB interface

jlinkels · 03-09-2015, 04:05 PM

I am testing a number of 3.5" hard disks. The disks have intermittent failures in a NAS device.

I have a USB/SATA enclosure which originally came with a 1 TB disk. I am testing a 3 TB disk with a GPT partition table.

This is what I see in /var/log/syslog:

Code:

Mar  9 20:47:23 donald-pc kernel: [613149.313768] sd 30:0:0:0: [sdb] 1565565872 512-byte logical blocks: (801 GB/746 GiB)
Mar  9 20:47:23 donald-pc kernel: [613149.314382] sd 30:0:0:0: [sdb] Write Protect is off
Mar  9 20:47:23 donald-pc kernel: [613149.314384] sd 30:0:0:0: [sdb] Mode Sense: 23 00 00 00
Mar  9 20:47:23 donald-pc kernel: [613149.315004] sd 30:0:0:0: [sdb] No Caching mode page found
Mar  9 20:47:23 donald-pc kernel: [613149.315007] sd 30:0:0:0: [sdb] Assuming drive cache: write through
Mar  9 20:47:23 donald-pc kernel: [613149.348343]  sdb: unknown partition table

I don't understand the 801GB size, but that might be due to an unreadable partition table.

Then using parted I see this:

Code:

root@donald-pc:~# parted /dev/sdb
GNU Parted 3.2
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
Error: Invalid argument during seek for read on /dev/sdb
Retry/Ignore/Cancel?

OK, the disk condition is unknown, so this is possible.

However, when I insert an identical disk which has been performing perfectly in the NAS, I receive exactly the same error.

Question is: Has the USB/SATA interface any influence on reading the disk when it is larger than a certain size?

jlinkels

Head_on_a_Stick · 03-09-2015, 05:03 PM

What is the output of:

Code:

# gdisk -l /dev/sdb

jlinkels · 03-09-2015, 06:25 PM

This seems more like invalid data than a hardware error, isn't it?

Code:

GPT fdisk (gdisk) version 0.8.10

Warning! Disk size is smaller than the main header indicates! Loading
secondary header from the last sector of the disk! You should use 'v' to
verify disk integrity, and perhaps options on the experts' menu to repair
the disk.
Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

Warning! One or more CRCs don't match. You should repair the disk!

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

****************************************************************************
Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.
****************************************************************************
Disk /dev/sdb: 1565565872 sectors, 746.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 8EE70EA7-5A50-4036-BA6B-1423B41854E2
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 8-sector boundaries
Total free space is 3907073537 sectors (1.8 TiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1           65536        42008576   20.0 GiB    0700  primary
   2        42008584      1953525106   911.5 GiB   0700  primary
root@donald-pc:~#

jlinkels

jlinkels · 03-09-2015, 07:59 PM

While I was experimenting with gdisk, this information was shown:

Code:

Disk /dev/sdb: 1565565872 sectors, 746.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 5F080231-6918-42E3-B8D9-1B61021ABC21

That is weird for a 3 TB disk.
Is there anything which could have ruined the size information.
Are there any tools to further query the disk?

jlinkels

jlinkels · 03-09-2015, 08:03 PM

Well, Google is also helpful.

http://askubuntu.com/questions/15168...tu-12-04-64bit

So the answer is: yes, it is likely the external USB/SATA interface is likely the culprit.

That answers this question, up to the next problem!

jlinkels