Manual: mkfs.exfat

mkfs.exfat(8)					   System Manager's Manual				       mkfs.exfat(8)

NAME
       mkfs.exfat - create an exFAT filesystem

SYNOPSIS
       mkfs.exfat  [ -b boundary_alignment ] [ -s sector_size ] [ -c cluster_size ] [ -f ] [ -C ] [ -h ] [ -L volume_label ]
       [ -U volume_guid ] [ --pack-bitmap ] [ -v ] device
       mkfs.exfat -V

DESCRIPTION
       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

OPTIONS
       -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
	      The default is always 1 MiB.

       -s, --sector-size=size
	      Specifies the sector size of the exFAT file system.  The size argument is specified in bytes or may be  speci‐
	      fied  with  k/K  suffix for kibibytes and must either 512, 1024, 2048 or 4096 bytes.  The default value is the
	      sector size reported by the device, or 512 bytes if the device sector size cannot be determined.

       -c, --cluster-size=size
	      Specifies the cluster size of the exFAT file system.  The size argument is specified in bytes or may be speci‐
	      fied with m/M suffix for mebibytes or k/K suffix for kibibytes and must be a power of two.  The default  value
	      is described in the following table:
						  Card Capacity Range	   Cluster Size
						  ──────────────────────────────────────
							    ≤256 MiB	       4 KiB
						  >256 MiB   ≤32 GiB	      32 KiB
						   >32 GiB		     128 KiB

       -f, --full-format
	      Performs a full format.  This zeros the entire disk device while creating the exFAT filesystem.

       -K, --no-discard
	      Do not attempt to discard blocks.

       -C, --verify-written
	      Verify  filesystem  metadata by reading it back after writing.  This option performs read-back verification of
	      critical exFAT metadata (boot record, FAT, allocation bitmap, upcase table, and  root  directory)	 after	each
	      formatting stage.	 It is useful for detecting broken storage devices or devices that falsely report successful
	      writes  without  actually	 persisting  data.   This  option may slightly degrade formatting performance and is
	      therefore disabled by default.

       -h, --help
	      Prints the help and exit.

       -L, --volume-label=label
	      Specifies the volume label to be associated with the exFAT filesystem.

       -U, --volume-guid=guid
	      Specifies the volume GUID to be associated with the exFAT filesystem.  It can be given in the  standard,	hyp‐
	      enized  UUID format like aaaabbbb-cccc-dddd-eeee-ffff00001111. Note: The volume GUID cannot be used to set the
	      the 8-letter ID reported by blkid or used as the filesystem UUID in /etc/fstab.

       --pack-bitmap
	      Attempts to relocate the exFAT allocation bitmap so that it ends at the alignment boundary immediately follow‐
	      ing 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 allow‐
	      ing 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 associ‐
	      ated 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.

       -q, --quiet
	      Prints only error messages while creating the exFAT filesystem.

       -v, --verbose
	      Prints verbose debugging information while creating the exFAT filesystem.

       -V, --version
	      Prints the version number and exits.

SEE ALSO
       mkfs(8), mount(8),

													       mkfs.exfat(8)