3TB external drive only seen as 746GB

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#1 Tue, 2018-01-02 05:00

jester465

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Joined: 2018-01-02

Hello I have been having a hard time getting a hard drive in an external usb enclosure to work on my mini pc. The drive worked just fine on Debian and windows. I tried to mount it inside of alpine and it didn't want to mount so i formatted the drive using dd to zero the drive in hopes to have alpine play nice with it. The drive still only shows as 746GB or so depending on which program you use. If I plug the drive into my windows machine it shows as 3tb no problem. Considering Windows can use the 3tb I do not believe its a hardware problem. Any advice would be much appreciated.

fdisk output:

#  fdisk -l /dev/sdb
Found valid GPT with protective MBR; using GPT
 
Disk /dev/sdb: 1565565872 sectors, 2580M
Logical sector size: 512
Disk identifier (GUID): bd9ba39a-196a-4385-9ef7-1d760fb7fe68
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1565565838
 
Number  Start (sector)    End (sector)  Size Name
     1            2048      1565564927  746G

parted output:

# parted /dev/sdb print
Model: WDC WD30 EFRX-68EUZN0 (scsi)
Disk /dev/sdb: 802GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
 
Number  Start   End    Size   File system  Name  Flags
 1      1049kB  802GB  802GB  ntfs

I have also found online to try gdisk so here is its output:

# gdisk -l /dev/sdb
GPT fdisk (gdisk) version 1.0.3
 
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present
 
Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 1565565872 sectors, 746.5 GiB
Model: EFRX-68EUZN0
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): BD9BA39A-196A-4385-9EF7-1D760FB7FE68
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 1565565838
Partitions will be aligned on 2048-sector boundaries
Total free space is 2925 sectors (1.4 MiB)
 
Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048      1565564927   746.5 GiB   8300

#2 Wed, 2018-01-03 09:18

ReproducibleBui...

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Last seen: 1 month 3 weeks ago
Joined: 2017-05-05

I'm no specialist, but I wonder whether your disk having a partition table formatted to 'GPT with protective MBR' might have something to do with Alpine not recognizing the whole 3tb. I have a usb pen drive that is formatted with MBR table instead, and Alpine mentions recognizing all 8Gb in it, even when I have only created a small partition within it. However, reformatting your USB hard drive to use an MBR partition table is not a solution, perhaps, as the latest Windows platforms may not use MBR, but GPT instead (I haven't researched this); you would, of course, have to backup your data first, as the Windows system and data would likely get messed up/lost. gdisk, by the way, which you used, is a version of fdisk more typically used for GPT than MBR, which is an older partition table type, if I am not mistaken.
Could anyone give better tips, if possible?

#3 Wed, 2018-01-03 16:10

jester465

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Last seen: 2 months 3 weeks ago
Joined: 2018-01-02

I have tried using parted mklabel gpt to rewrite the partition table to gpt and it still lists a protective mbr.