external disk weirdness

[przxqgl]

i am running trusty, and i have a 3TB external (USB) hard disk that i have partitioned into 2 partitions, one 1TB and one 2TB (approximately). i have them mounted at /media/home and /media/backup, they mount at startup, and everything works the way i would expect it to.

until i decide to upgrade my box (the old box didn't have as much memory, and one of the two internal hard disks was dying).

when i got the new box up and running, even with the USB drive plugged in, it doesn't mount, and it doesn't even show up in /dev that i can see...

i had a similar problem a while ago, which i fixed using the instructions found here -- https://www.kubuntuforums.net/showth...-my-USB-drives -- but when i tried that, it didn't make any obvious difference.

any clues?

[vinnywright]

with the drive pluged in do you see it with

sudo parted -l

?

VINNY

[przxqgl]

with the drive pluged in do you see it with

sudo parted -l

Model: ATA WDC WD10EZEX-60M (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  984GB   984GB   primary   ext4         boot
 2      984GB   1000GB  16.3GB  extended
 5      984GB   1000GB  16.3GB  logical


Model: SanDisk Cruzer Fit (scsi)
Disk /dev/sdb: 16.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      16.4kB  16.0GB  16.0GB  primary  ext4         lba


Model:  USB DISK 2.0 (scsi)
Disk /dev/sdc: 4008MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      4129kB  4008MB  4004MB  primary  fat32        lba

i think so, is that disk at /dev/sdc the disk? 4008MB seems about right...

[vinnywright]

Model: ATA WDC WD10EZEX-60M (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  984GB   984GB   primary   ext4         boot
 2      984GB   1000GB  16.3GB  extended
 5      984GB   1000GB  16.3GB  logical


Model: SanDisk Cruzer Fit (scsi)
Disk /dev/sdb: 16.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      16.4kB  16.0GB  16.0GB  primary  ext4         lba


Model:  USB DISK 2.0 (scsi)
Disk /dev/sdc: 4008MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      4129kB  4008MB  4004MB  primary  fat32        lba

i think so, is that disk at /dev/sdc the disk? 4008MB seems about right...

about 1000MB is 1GB ,,,,,,,,,,1000GB IS 1TB ,,,,,,,so no this is a 4GB disk + you say you partitioned it (the 3TB disk) into 2 partitions ,,,sdc is 1 partition formated fat32

VINNY

[przxqgl]

in that case, no, i can't see the disk using "sudo parted -l"...

and, additionally, i've got a mysterious, unknown disk at /dev/sdc... 8/

you say you partitioned it (the 3TB disk) into 2 partitions ,,,sdc is 1 partition formated fat32

if it didn't change anything when i partitioned it, then, yes, /dev/sdc is, possibly, one of the partitions...

how do i get it to mount, and how do i get the other partition to show up?

[vinnywright]

in that case, no, i can't see the disk using "sudo parted -l"...

and, additionally, i've got a mysterious, unknown disk at /dev/sdc... 8/



if it didn't change anything when i partitioned it, then, yes, /dev/sdc is, possibly, one of the partitions...

how do i get it to mount, and how do i get the other partition to show up?

well first what did you partition it with ,,,,,,?

you can mount it diferent way's ,,,,in dolphin by clicking it in the places panel if it is showing ,,,,,,,,,,,,,,, or on the CLI with something like

"make a place to mount it"

sudo mkdir /mnt/disk

"mount it to /mnt/disk"

sudo mount -t fat32 /dev/sdc1 /mnt/disk

now navigate to /mnt/disk in dolphin and see whats in their.

if you have permissions problems use a root dolphin

kdesudo dolphin

if this is the disk we can start working out the problems with getting it to auto mount and your user access rites

VINNY

[przxqgl]

well first what did you partition it with ,,,,,,?

KDE Partition Manager

you can mount it diferent way's ,,,,in dolphin by clicking it in the places panel if it is showing

it is not showing up in dolphin at all.

"make a place to mount it"

sudo mkdir /mnt/disk

"mount it to /mnt/disk"

sudo mount -t fat32 /dev/sdc1 /mnt/disk

mount: unknown filesystem type 'fat32'
mount: maybe you meant 'vfat'?

so, do i mean 'vfat'? i'm not even sure what 'vfat' is... very fat?

[vinnywright]

1 more thing fat32 will not suport a disk that large ,,,if it is 3TB ,,,,fat will only see 4GB I think .

you should repartition it as NTFS if windows neads to use it ,,,, or ext4 if linux only.

VINNY

[vinnywright]

to be sure /dev/sdc is the disk ,,,,shutdown the box ,,,,unplug it ,,,,reboot and run the parted command again and see if /dev/sdc is gone ,,,,,,plug it back in run the parted command ,,,,is it back ?

if yes use the partition manager to repartition it as NTFS or ext4

VINNY

[przxqgl]

1 more thing fat32 will not suport a disk that large ,,,if it is 3TB ,,,,fat will only see 4GB I think .

i will definitely do that, but it's going to have to be after i take the data off and store it somewhere else, because, if i recall correctly, formatting the disk means erasing all of the data contained therein, and that's what i'm trying to avoid... it was called /media/backup for a reason...

you should repartition it as NTFS if windows neads to use it ,,,, or ext4 if linux only.

i understand, and there is no reason to format it FAT32 or NTFS, because i only use linux and mac... but, as i said, the disks (or, rather, the partitions) are going to have to be cleared of all their data before i reformat them, otherwise even worse things are likely to happen than have already happened.

[vinnywright]

so what was it formated to when you originally made it for a backup disk ?

VINNY

[przxqgl]

i didn't reformat it, i went straight to partitioning it, so if it was FAT32 when i bought it, then it's no surprise that that's what it is now...

however, here's an interesting tidbit. i turned off my machine, unplugged the disk, then turned the machine on again and ran the "parted" command, which said:

Model: ATA WDC WD10EZEX-60M (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  984GB   984GB   primary   ext4         boot
 2      984GB   1000GB  16.3GB  extended
 5      984GB   1000GB  16.3GB  logical

(yes, i also unplugged all of the other USB disks, as well)

now, here's the interesting part. when i plugged the 3TB, 2 partition disk in again, this is what it said:

Error: The backup GPT table is corrupt, but the primary appears OK, so that will
be used.
OK/Cancel? ok                                                             
Model: WD My Book 1130 (scsi)
Disk /dev/sdb: 3001GB
Sector size (logical/physical): 4096B/4096B
Partition Table: gpt

Number  Start   End     Size    File system  Name                  Flags
 1      24.6kB  210MB   210MB                EFI System Partition  boot
 2      210MB   2000GB  2000GB               backup
 3      2000GB  3000GB  1000GB               home

it's a start, no?

[Qqmike]

I don't think I have studied this thread as carefully as I should, but I'm on the run, don't want to interrupt the flow here, just two things strike me (quickly):

The traditional MBR partitioning scheme only sees up to 2 TB. Thus, the GPT is better for very large disks.

sudo gdisk -l /dev/sdx will tell you if it sees a GPT partitioned disk and if it is healthy or broken. If it is broken, the interactive form of gdisk can probably fix it: sudo gdisk /dev/sdx (with no options).

[przxqgl]

sudo gdisk -l /dev/sdx will tell you if it sees a GPT partitioned disk and if it is healthy or broken. If it is broken, the interactive form of gdisk can probably fix it: sudo gdisk /dev/sdx (with no options).

"sudo gdisk -l /dev/sdb" gave me the following:

GPT fdisk (gdisk) version 0.8.8

Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

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: 732558336 sectors, 2.7 TiB
Logical sector size: 4096 bytes
Disk identifier (GUID): 8E2D5510-7E63-4F58-8836-5F35FFB08726
Partition table holds up to 128 entries
First usable sector is 6, last usable sector is 732558330
Partitions will be aligned on 8-sector boundaries
Total free space is 65536 sectors (256.0 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1               6           51205   200.0 MiB   EF00  EFI System Partition
   2           51206       488332461   1.8 TiB     AF00  backup
   3       488365230       732525562   931.4 GiB   AF00  home

once again, i'm not a linux genius, but my impression is that amounts to "broken"...

"sudo gdisk /dev/sdb" says this:

GPT fdisk (gdisk) version 0.8.8

Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

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.
****************************************************************************

Command (? for help):

and, because of the fact that i'm no linux genius, i don't know what to do next... ? for help told me how to verify the disk (it's okay, unsurprisingly), but it didn't tell me how to recover... help?

[oshunluvr]

Since it's a USB disk, start at the beginning and verify it's working. With the drive unplugged, open a terminal and type dmesg. You'll see a bunch of stuff on the screen. Then plug the drive in and type dmesg again. If the drive doesn't appear in the dmesg output, including a list of it's partitions, it not being detected properly. If you do see output showing the partitions (/dev/sdc1 etc...) then we can move forward.

Re. fat (aka fat16) vfat and fat32 - vfat is an extension of fat16, fat32 is an extension of vfat and not normally used with linux. fat32/vfat have a file size limit of 4GB but can be used on larger volumes than that - up to 8TB for fat32.

As far as the reformat - there's ways to handle that if you have a lot of space on the drive.