597. Missing partition -- gparted shows unallocated space

The issue:
I'm low on space on my / partition since ECCE has a way of putting really large files in /tmp. Rather than trying to fix the behaviour of ECCE, I'm planning on moving /tmp to a separate disk that's dedicated to highio processes and where ECCE can't cause my / to fill up. I might move /opt as well, to free even more space. The first step in such a move is to create an additional partition on your target disk and for that gparted is good as it can move all the data before creating the new partition.

Imagine my surprise when I fired up gparted and saw:

Using Disk Utilities (palimpsest) it doesn't look too odd:

Using fdisk I see a complete lack of partitions:

sudo fdisk /dev/sdb

Command (m for help): p
Disk /dev/sdb: 1000 GB, 1000202273280 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System 
Command (m for help):                   

---

This may be a job for testdisk. I fired it up with sudo, selected Intel type partition, and kept selecting the defaults -- eventually my partition showed up. I then did a deep search to make sure everything was ok.

I then check using palimpsest and gparted:

(I also screwed up, then fixed a disk with a different issue -- but because I'm not really sure what I did to fix it I'll make a separate post about that at a later date. Maybe.)

279. Formatting and adding a disk with fdisk

I've got a box with two harddrives -- sda (160 gb) has debian and sdb has CentOS (500 gb). I never use CentOS and I need the space for debian.

sudo fdisk -l

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1   312581807   156290903+  ee  GPT

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0007e385

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *          63    32772599    16386268+  83  Linux
/dev/sdb2        32772600    40965749     4096575   83  Linux
/dev/sdb3        40965750    43006004     1020127+  82  Linux swap / Solaris
/dev/sdb4        43006005   976768064   466881030    5  Extended
/dev/sdb5        43006068   976768064   466880998+  83  Linux

We're in 'luck' since we're only interested in killing sdb, and gparted wants a Display (this is done remotely).
So

sudo fdisk /dev/sdb

Command (m for help): d
Partition number (1-5): 1

Command (m for help): d 
Partition number (1-5): 2

Command (m for help): d
Partition number (1-5): 3

Command (m for help): d
Partition number (1-5): 4

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

So did it work?

 sudo fdisk -l

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.


Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1   312581807   156290903+  ee  GPT

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0007e385

   Device Boot      Start         End      Blocks   Id  System

Time to create a new partition

sudo fdisk /dev/sdb

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 
Using default value 1
First sector (2048-976773167, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-976773167, default 976773167): 
Using default value 976773167

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

Did it work?

sudo fdisk -l /dev/sdb

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
81 heads, 63 sectors/track, 191411 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0007e385

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048   976773167   488385560   83  Linux

Create a file system:

sudo mkfs.ext4 /dev/sdb1

mke2fs 1.42.5 (29-Jul-2012)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
30531584 inodes, 122096390 blocks
6104819 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
3727 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 
        102400000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done     

Let's automount it:

mkdir /home/me/scratch

and edit /etc/fstab

/dev/sdb1  /home/me/scratch    ext4    defaults        0       2

You're done.