1mkfs.exfat(8) System Manager's Manual mkfs.exfat(8)
2
6 mkfs.exfat - create an exFAT filesystem
7
9 mkfs.exfat [ -b boundary_alignment ] [ -c cluster_size ] [ -f ] [ -h ]
10 [ -L volume_label ] [ --pack-bitmap ] [ -v ] device
11 mkfs.exfat -V
12
14 mkfs.exfat creates an exFAT filesystem by writing on a special file us‐
15 ing the values found in the arguments of the command line. It is in‐
16 voked automatically by mkfs(8) when it is given the -t exfat option.
17 As an example, to make a filesystem on the first partition on the first
19 SCSI disk, use:
20 mkfs.exfat /dev/sda1
22
24 -b, --boundary-align=alignment
25 Specifies the alignment for the FAT and the start of the cluster
26 heap. The alignment argument is specified in bytes or may be
27 specified with m/M suffix for mebibytes or k/K suffix for
28 kibibytes and should be a power of two. Some media like SD
29 cards need this for optimal performance and endurance, in which
30 case alignment should be set to half of the card's native bound‐
31 ary unit size. If the card's native boundary unit size is not
32 known, refer to the following table of boundary unit sizes rec‐
33 ommended by the SD Card Association.
34 Card Capacity Range Cluster Size Boundary Unit
36 ──────────────────────────────────────────────────────
37 ≤8 MiB 8 KiB 8 KiB
38 >8 MiB ≤64 MiB 16 KiB 16 KiB
39 >64 MiB ≤256 MiB 16 KiB 32 KiB
40 >256 MiB ≤1 GiB 16 KiB 64 KiB
41 >1 GiB ≤2 GiB 32 KiB 64 KiB
42 >2 GiB ≤32 GiB 32 KiB 4 MiB
43 >32 GiB ≤128 GiB 128 KiB 16 MiB
44 >128 GiB ≤512 GiB 256 KiB 32 MiB
45 >512 GiB ≤2 TiB 512 KiB 64 MiB
46 -c, --cluster-size=size
48 Specifies the cluster size of the exFAT file system. The size
49 argument is specified in bytes or may be specified with m/M suf‐
50 fix for mebibytes or k/K suffix for kibibytes and must be a
51 power of two.
52 -f, --full-format
54 Performs a full format. This zeros the entire disk device while
55 creating the exFAT filesystem.
56 -h, --help
58 Prints the help and exit.
59 -L, --volume-label=label
61 Specifies the volume label to be associated with the exFAT
62 filesystem.
63 --pack-bitmap
65 Attempts to relocate the exFAT allocation bitmap so that it ends
66 at the alignment boundary immediately following the FAT rather
67 than beginning at that boundary. This strictly violates the SD
68 card specification but may improve performance and endurance on
69 SD cards and other flash media not designed for use with exFAT
70 by allowing file-system metadata updates to touch fewer flash
71 allocation units. Furthermore, many SD cards and other flash
72 devices specially optimize the allocation unit where the FAT re‐
73 sides so as to support tiny writes with reduced write amplifica‐
74 tion but expect only larger writes in subsequent allocation
75 units — where the exFAT bitmap would be placed by default.
76 Specifying --pack-bitmap attempts to avoid the potential prob‐
77 lems associated with issuing many small writes to the bitmap by
78 making it share an allocation unit with the FAT. If there is
79 insufficient space for the bitmap there, then this option will
80 have no effect, and the bitmap will be aligned at the boundary
81 as by default.
82 -v, --verbose
84 Prints verbose debugging information while creating the exFAT
85 filesystem.
86 -V, --version
88 Prints the version number and exits.
89
91 mkfs(8), mount(8),
92 mkfs.exfat(8)