gdisk partition expansion.md

Install gdisk, an fdisk-style tool for GUID Partition Tables (GPT)

# yum -y install gdisk

Observe tool's version

[root@ /]# gdisk
GPT fdisk (gdisk) version 0.8.10

Type device filename, or press <Enter> to exit:

Examine the storage device list
Note device xvda has 10G capacity; partition xvda1 uses only 6G

[root@ /]# lsblk
NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  10G  0 disk
└─xvda1 202:1    0   6G  0 part /
xvdb    202:16   0  75G  0 disk /mnt
xvdc    202:32   0  75G  0 disk /data0
xvdd    202:48   0  50G  0 disk

Create GUID Partition Table (GPT) map for partition xvda1

[root@ /]# gdisk /dev/xvda1
GPT fdisk (gdisk) version 0.8.10

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

Creating new GPT entries.

Use ? to list available commands

Command (? for help): ?
b back up GPT data to a file
c change a partition's name
d delete a partition
i show detailed information on a partition
l list known partition types
n add a new partition
o create a new empty GUID partition table (GPT)
p print the partition table
q quit without saving changes
r recovery and transformation options (experts only)
s sort partitions
t change a partition's type code
v verify disk
w write table to disk and exit
x extra functionality (experts only)
? print this menu

p - print the partition table to get the GUID

Command (? for help): p
Disk /dev/xvda1: 12582912 sectors, 6.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): BA7F7199-B97B-4A68-858C-10D82D732633
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 12582878
Partitions will be aligned on 2048-sector boundaries
Total free space is 12582845 sectors (6.0 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name

Command (? for help): q

Run gdisk again to pick up new GPT entry

[root@ /]# gdisk /dev/xvda
GPT fdisk (gdisk) version 0.8.10

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

Found valid GPT with protective MBR; using GPT.

Command (? for help): p
Disk /dev/xvda: 20971520 sectors, 10.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 0B62AD67-7BC0-452B-B7D7-9932C0E922EE
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 20971486
Partitions will be aligned on 2048-sector boundaries
Total free space is 8388541 sectors (4.0 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048        12584959   6.0 GiB     EF00

o - create a new empty GUID partition table (GPT)

Command (? for help): o
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y

n - add a new partition

Command (? for help): n
Partition number (1-128, default 1):
First sector (34-20971486, default = 2048) or {+-}size{KMGTP}:
Last sector (2048-20971486, default = 20971486) or {+-}size{KMGTP}:
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300):
Changed type of partition to 'Linux filesystem'

t - change a partition's type code

Command (? for help): t
Using 1
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300): EF00
Changed type of partition to 'EFI System'

x - extra functionality (experts only)

Command (? for help): x

g - Identify partition by GUID
The value entered is copied from output above

Expert command (? for help): g
Enter the disk's unique GUID ('R' to randomize): 0B62AD67-7BC0-452B-B7D7-9932C0E922EE
The new disk GUID is 0B62AD67-7BC0-452B-B7D7-9932C0E922EE

w - write table to disk and exit

Expert command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/xvda.
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot.
The operation has completed successfully.

Since we've modified the root volume, we must reboot for the new partition table to take effect

[root@ /]# df
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/xvda1       6061632  5730976     16084 100% /
tmpfs           15405056        0  15405056   0% /dev/shm
/dev/xvdb       77398536 14761528  58705388  21% /mnt
/dev/xvdc       77398536   184216  73282700   1% /data0
cm_processes    15405056     2584  15402472   1% /mnt/var/run/cloudera-scm-agent/process
[root@ /]# reboot

Broadcast message from [email protected]
(/dev/pts/1) at 15:21 ...

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