mkfs.ext4

Create an ext4 filesystem on a device

TLDR

Create ext4 filesystem

$ sudo mkfs.ext4 /dev/sdXY

Create with volume label

$ sudo mkfs.ext4 -L [label] /dev/sdXY

Create with reduced reserved blocks (1% instead of 5%)

$ sudo mkfs.ext4 -m [1] /dev/sdXY

Create with specific block size

$ sudo mkfs.ext4 -b [4096] /dev/sdXY

Create with specific owner and UUID

$ sudo mkfs.ext4 -E root_owner=[uid]:[gid] -U [uuid] /dev/sdXY

Quiet creation (for scripts)

$ sudo mkfs.ext4 -q /dev/sdXY

SYNOPSIS

mkfs.ext4 [options] device [blocks-count]

DESCRIPTION

mkfs.ext4 creates an ext4 filesystem on a device. ext4 is the default Linux filesystem, offering journaling, large file support, and excellent performance. It is equivalent to mke2fs -t ext4.

PARAMETERS

-L LABEL

Set volume label (max 16 characters).

-b BLOCKSIZE

Set block size in bytes (1024, 2048, or 4096).

-m PERCENT

Reserved blocks percentage for super-user (default: 5%).

-i BYTESPERINODE

Set bytes per inode ratio.

-N INODES

Set number of inodes.

-U UUID

Set filesystem UUID.

-E OPTIONS

Extended options (comma-separated), e.g. root_owner=uid:gid, discard, stride=N, stripe-width=N.

-O FEATURES

Set filesystem features (comma-separated), e.g. ^hasjournal, extent, dirindex.

-T USAGETYPE_

Specify usage type (e.g. largefile, largefile4, news, small) to set default parameters.

-c

Check the device for bad blocks before creating the filesystem.

-cc

Perform a slower, destructive read-write bad blocks test.

-n

Dry run; show what would be done without creating the filesystem.

-F

Force creation even if the device is not a block special device or appears in use.

-q

Quiet execution.

All data on device will be lost. Part of e2fsprogs package. Default reserved blocks (5%) can be reduced for non-root filesystems with -m. Use -F twice to force creation on a mounted device. Equivalent to mke2fs -t ext4.