GNU Parted

Related articles:
• fdisk




• Partitioning

GNU Parted is a program for creating and manipulating partition tables. GParted is a GUI frontend.

1 Installation

Install the parted package. For a graphical interface, install the gparted package, the graphical frontend to parted.

2 Usage

Parted has two modes: command line and interactive. Parted should always be started with:

# parted device

where device is the hard disk device to edit (for example /dev/sda). If you omit the device argument, parted will attempt to guess which device you want.

2.1 Command line mode

In command line mode, this is followed by one or more commands. For example:

# parted /dev/sda mklabel gpt mkpart P1 ext3 1MiB 8MiB 

Note: Options (like --help) can only be specified on the command line.

2.2 Interactive mode

Interactive mode simplifies the partitioning process and reduces unnecessary repetition by automatically applying all partitioning commands to the specified device.

In order to start operating on a device, execute:

# parted /dev/sdx

You will notice that the command-line prompt changes from a hash (#) to (parted): this also means that the new prompt is not a command to be manually entered when running the commands in the examples.

To see a list of the available commands, enter:

(parted) help

When finished, or if wishing to implement a partition table or scheme for another device, exit from parted with:

(parted) quit

After exiting, the command-line prompt will change back to #.

If you do not give a parameter to a command, Parted will prompt you for it. For example:

(parted) mklabel
New disk label type? gpt

3 Rounding

Since many partitioning systems have complicated constraints, Parted will usually do something slightly different to what you asked. (For example, create a partition starting at 10.352Mb, not 10.4Mb) If the calculated values differ too much, Parted will ask you for confirmation. If you know exactly what you want, or to see exactly what Parted is doing, it helps to specify partition endpoints in sectors (with the "s" suffix) and give the "unit s" command so that the partition endpoints are displayed in sectors.

As of parted-2.4, when you specify start and/or end values using IEC binary units like “MiB”, “GiB”, “TiB”, etc., parted treats those values as exact, and equivalent to the same number specified in bytes (i.e., with the “B” suffix), in that it provides no “helpful” range of sloppiness. Contrast that with a partition start request of “4GB”, which may actually resolve to some sector up to 500MB before or after that point. Thus, when creating a partition, you should prefer to specify units of bytes (“B”), sectors (“s”), or IEC binary units like “MiB”, but not “MB”, “GB”, etc.

4 Partitioning

4.1 Create new partition table

You need to (re)create the partition table of a device when it has never been partitioned before, or when you want to change the type of its partition table. Recreating the partition table of a device is also useful when the partition scheme needs to be restructured from scratch.

Open each device whose partition table must be (re)created with:

# parted /dev/sdx

To then create a new MBR/msdos partition table for BIOS systems, use the following command:

(parted) mklabel msdos

To create a new GPT partition table for UEFI systems instead, use:

(parted) mklabel gpt

4.2 Partition schemes

You can decide the number and size of the partitions the devices should be split into, and which directories will be used to mount the partitions in the installed system (also known as mount points). The mapping from partitions to directories is the partition scheme, which must comply with the following requirements:

• At least a partition for the / (root) directory must be created.
• When using a UEFI motherboard, one EFI System Partition must be created

In the examples below it is assumed that a new and contiguous partitioning scheme is applied to a single device. Some optional partitions will also be created for the /boot and /home directories: see also Parabola filesystem hierarchy for an explanation of the purpose of the various directories; if separate partitions for directories like /boot or /home are not created, these will simply be contained in the / partition. Also the creation of an optional partiton for swap space will be illustrated.

If not already open in a parted interactive session, open each device to be partitioned with:

# parted /dev/sdx

The following command will be used to create partitions:

(parted) mkpart part-type fs-type start end

• part-type is one of primary, extended or logical, and is meaningful only for MBR partition tables.
• fs-type is an identifier chosen among those listed by entering help mkpart as the closest match to the file system that you will use. The mkpart command does not actually create the file system: the fs-type parameter will simply be used by parted to set a 1-byte code that is used by boot loaders to "preview" what kind of data is found in the partition, and act accordingly if necessary. See also Wikipedia:Disk partitioning#PC partition types.

Tip: Most Linux native file systems map to the same partition code (0x83), so it is perfectly safe to e.g. use ext2 for an ext4-formatted partition.

• start is the beginning of the partition from the start of the device. It consists of a number followed by a unit, for example 1M means start at 1MiB.
• end is the end of the partition from the start of the device (not from the start value). It has the same syntax as start, for example 100% means end at the end of the device (use all the remaining space).

Warning: It is important that the partitions do not overlap each other: if you do not want to leave unused space in the device, make sure that each partition starts where the previous one ends.

Note: parted may issue a warning like:

Warning: The resulting partition is not properly aligned for best performance.
Ignore/Cancel?

In this case, read Partitioning#Partition alignment and follow #Alignment to fix it.

The following command will be used to flag the partition that contains the /boot directory as bootable:

(parted) set partition boot on

• partition is the number of the partition to be flagged (see the output of the print command).

4.2.1 UEFI/GPT examples

In every instance, a special bootable EFI System Partition is required.

If creating a new EFI System Partition, use the following commands (the recommended size is 512MiB):

(parted) mkpart ESP fat32 1MiB 513MiB
(parted) set 1 boot on

The remaining partition scheme is entirely up to you. For one other partition using 100% of remaining space:

(parted) mkpart primary ext4 513MiB 100%

For separate / (20GiB) and /home (all remaining space) partitions:

(parted) mkpart primary ext4 513MiB 20.5GiB
(parted) mkpart primary ext4 20.5GiB 100%

And for separate / (20GiB), swap (4GiB), and /home (all remaining space) partitions:

(parted) mkpart primary ext4 513MiB 20.5GiB
(parted) mkpart primary linux-swap 20.5GiB 24.5GiB
(parted) mkpart primary ext4 24.5GiB 100%

4.2.2 BIOS/MBR examples

For a minimum single primary partition using all available disk space, the following command would be used:

(parted) mkpart primary ext4 1MiB 100%
(parted) set 1 boot on

In the following instance, a 20GiB / partition will be created, followed by a /home partition using all the remaining space:

(parted) mkpart primary ext4 1MiB 20GiB
(parted) set 1 boot on
(parted) mkpart primary ext4 20GiB 100%

In the final example below, separate /boot (100MiB), / (20GiB), swap (4GiB), and /home (all remaining space) partitions will be created:

(parted) mkpart primary ext3 1MiB 100MiB
(parted) set 1 boot on
(parted) mkpart primary ext3 100MiB 20GiB
(parted) mkpart primary linux-swap 20GiB 24GiB
(parted) mkpart primary ext3 24GiB 100%

4.3 Resizing Partitions

Warning: Partitions that are being resized must be unmounted and not in use. If it cannot be done (e.g. the partition that mounts to /), use a live media/rescue system.

Note:

• You can only move the end of the partition with parted.
• As of parted v4.2 resizepart may need the use of #Interactive mode.[1]
• These instructions apply to partitions that have ext2, ext3 or ext4 filesystems.

If you are growing a partition, you have to first resize the partition and then resize the filesystem on it, while for shrinking the filesystem must be resized before the partition to avoid data loss.

4.3.1 Growing partitions

To grow a partition (in parted interactive mode):

(parted) resizepart number end

Where number is the number of the partition you are growing, and end is the new end of the partition (which needs to be larger than the old end).

Then, to grow the filesystem on the partition:

# resize2fs /dev/sdaX size

Where sdaX stands for the partition you are growing, and size is the new size of the partition.

4.3.2 Shrinking partitions

To shrink the filesystem on the partition:

# resize2fs /dev/sdaX size

Where sdaX stands for the partition you are shrinking, and size is the new size of the partition.

Then shrink the partition (in parted interactive mode):

(parted) resizepart number end

Where number is the number of the partition you are shrinking, and end is the new end of the partition (which needs to be smaller than the old end).

When done, use the resizepart command from util-linux to tell the kernel about the new size:

# resizepart device number size

Where device is the device that holds the partition, number is the number of the partition and size is the new size of the partition.

5 Warnings

Parted will always warn you before doing something that is potentially dangerous, unless the command is one of those that is inherently dangerous (viz., rm, mklabel and mkpart).

5.1 Alignment

When creating a partition, parted might warn about improper partition alignment but does not hint about proper alignment. For example:

(parted) mkpart primary fat16 0 32M
Warning: The resulting partition is not properly aligned for best performance.
Ignore/Cancel?                                                     

The warning means the partition start is not aligned. Enter "Ignore" to go ahead anyway, print the partition table in sectors to see where it starts, and remove/recreate the partition with the start sector rounded up to increasing powers of 2 until the warning stops. As one example, on a flash drive with 512B sectors, Parted wanted partitions to start on sectors that were a multiple of 2048, which is 1 MiB alignment.

If you want parted to attempt to calculate the correct alignment for you, specify the start position as 0% instead of some concrete value. To make one large ext4 partition, your command would look like this:

(parted) mkpart primary ext4 0% 100%

6 Tips and tricks

6.1 Fixing messed-up partition order

See Fdisk#Sort_partitions.

Note: You must run partprobe as root or reboot the system in order for the kernel to read the new partition table!

6.2 Check alignment

On an already partitioned disk, you can use parted to verify the alignment of a partition on a device. For instance, to verify alignment of partition 1 on /dev/sda:

# parted /dev/sda
(parted) align-check optimal 1
1 aligned

7 See also

• GNU parted - Parted User's Manual
• How to align partitions for best performance using parted
• Resize an ext3/ext4 partition
• Official GParted forums

8 Acknowledgement

This wiki article is based on ArchWiki. We may have removed non-FSDG bits from it.