mkfs.exfat - create an exFAT filesystem
mkfs.exfat [ -b boundary_alignment ] [
-c cluster_size ] [ -f ] [ -h ] [ -L
volume_label ] [ --pack-bitmap ] [ -v ] device
mkfs.exfat -V
mkfs.exfat creates an exFAT filesystem by writing on a
special file using the values found in the arguments of the command line. It
is invoked automatically by mkfs(8) when it is given the -t
exfat option.
As an example, to make a filesystem on the first partition on the
first SCSI disk, use:
- mkfs.exfat /dev/sda1
- -b,
--boundary-align=alignment
- Specifies the alignment for the FAT and the start of the cluster heap. The
alignment argument is specified in bytes or may be specified with
m/M suffix for mebibytes or k/K suffix for
kibibytes and should be a power of two. Some media like SD cards need this
for optimal performance and endurance, in which case alignment
should be set to half of the card's native boundary unit size. If the
card's native boundary unit size is not known, refer to the following
table of boundary unit sizes recommended by the SD Card Association.
| Card Capacity
Range |
Cluster Size |
Boundary Unit |
| |
≤8
MiB |
8 KiB |
8 KiB |
| >8
MiB |
≤64
MiB |
16 KiB |
16 KiB |
| >64
MiB |
≤256
MiB |
16 KiB |
32 KiB |
| >256
MiB |
≤1
GiB |
16 KiB |
64 KiB |
| >1
GiB |
≤2
GiB |
32 KiB |
64 KiB |
| >2
GiB |
≤32
GiB |
32 KiB |
4 MiB |
| >32
GiB |
≤128
GiB |
128 KiB |
16 MiB |
| >128
GiB |
≤512
GiB |
256 KiB |
32 MiB |
| >512
GiB |
≤2
TiB |
512 KiB |
64 MiB |
- -c,
--cluster-size=size
- Specifies the cluster size of the exFAT file system. The size
argument is specified in bytes or may be specified with m/M
suffix for mebibytes or k/K suffix for kibibytes and must be
a power of two.
- -f,
--full-format
- Performs a full format. This zeros the entire disk device while creating
the exFAT filesystem.
- -h, --help
- Prints the help and exit.
- -L,
--volume-label=label
- Specifies the volume label to be associated with the exFAT
filesystem.
- --pack-bitmap
- Attempts to relocate the exFAT allocation bitmap so that it ends at the
alignment boundary immediately following the FAT rather than beginning at
that boundary. This strictly violates the SD card specification but may
improve performance and endurance on SD cards and other flash media not
designed for use with exFAT by allowing file-system metadata updates to
touch fewer flash allocation units. Furthermore, many SD cards and other
flash devices specially optimize the allocation unit where the FAT resides
so as to support tiny writes with reduced write amplification but expect
only larger writes in subsequent allocation units — where the exFAT
bitmap would be placed by default. Specifying --pack-bitmap
attempts to avoid the potential problems associated with issuing many
small writes to the bitmap by making it share an allocation unit with the
FAT. If there is insufficient space for the bitmap there, then this option
will have no effect, and the bitmap will be aligned at the boundary as by
default.
- -v, --verbose
- Prints verbose debugging information while creating the exFAT
filesystem.
- -V, --version
- Prints the version number and exits.