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How can I create a disk partition on a disk that is greater than 2TB in size on Red Hat Enterprise Linux?

March 15, 2020 at 12:59 pm Leave a comment

When we try to partition a disk that is larger than 2 TB , you must use the parted utility instead of fdisk. In this example I am referring to my disk as /dev/sdj

#parted /dev/sdj
Using /dev/sdj
Welcome to GNU Parted! Type ‘help’ to view a list of commands.
(parted)

#(parted) mklabel —–> This will create a GPT label on the disk.
Warning: The existing disk label on /dev/sdj will be destroyed and all data on this disk will be lost. Do you want to continue?
Yes/No? Yes
New disk label type? [gpt]? gpt
(parted)

(parted) print  

Model: Linux device-mapper (dm)
Disk /dev/sdj: 5662310.4MB ————-> Note down this value as we will be using it the below commands)
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags

Create the partition:
(parted) mkpart primary 0 5662310.4MB

(parted) print ——–> Use this command to verify the partition created.

Unlike , the fdisk , you don’t need to issue the write command to save the changes. Simply type quit to exit from the parted utility. Thereafter , you could proceed with the file system creation.

Root Cause

The fdisk command only supports the legacy MBR partition table format (also known as msdos partition table)

* MBR partition tables use data fields that have a maximum of 32 bit sector numbers, and with 512 bytes/sector that means a maximum of 2^(32+9) bytes per disk or partition is supported.
*MBR partition table can not support accessing data on disks past 2.19TB due to the above limitation
Note that some older versions of fdisk may permit a larger size to be created but the resulting partition table will be invalid.

The parted command can create disk labels using MBR (msdos), GUID Partition Table (GPT), SUN disk labels and many more types.

* The GPT disk label overcomes many of the limitations of the DOS MBR including restrictions on the size of the disk, the size of any one partition and the overall number of partitions.
* Note that booting from a GPT labelled volume requires firmware support and this is not commonly available on non-EFI platforms (including x86 and x86_64 architectures).

Source:
https://access.redhat.com/solutions/4281 

Entry filed under: Linux.