1mkfs.exfat(8) System Manager's Manual mkfs.exfat(8)
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6 mkfs.exfat - create an exFAT filesystem
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9 mkfs.exfat [ -b boundary_alignment ] [ -c cluster_size ] [ -f ] [ -h ]
10 [ -L volume_label ] [ -U volume_guid ] [ --pack-bitmap ] [ -v ] device
11 mkfs.exfat -V
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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
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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 The default is always 1 MiB.
47 -c, --cluster-size=size
49 Specifies the cluster size of the exFAT file system. The size
50 argument is specified in bytes or may be specified with m/M suf‐
51 fix for mebibytes or k/K suffix for kibibytes and must be a
52 power of two. The default value is described in the following
53 table:
54 Card Capacity Range Cluster Size
56 ──────────────────────────────────────
57 ≤256 MiB 4 KiB
58 >256 MiB ≤32 GiB 32 KiB
59 >32 GiB 128 KiB
60 -f, --full-format
62 Performs a full format. This zeros the entire disk device while
63 creating the exFAT filesystem.
64 -h, --help
66 Prints the help and exit.
67 -L, --volume-label=label
69 Specifies the volume label to be associated with the exFAT
70 filesystem.
71 -U, --volume-guid=guid
73 Specifies the volume GUID to be associated with the exFAT
74 filesystem.
75 --pack-bitmap
77 Attempts to relocate the exFAT allocation bitmap so that it ends
78 at the alignment boundary immediately following the FAT rather
79 than beginning at that boundary. This strictly violates the SD
80 card specification but may improve performance and endurance on
81 SD cards and other flash media not designed for use with exFAT
82 by allowing file-system metadata updates to touch fewer flash
83 allocation units. Furthermore, many SD cards and other flash
84 devices specially optimize the allocation unit where the FAT re‐
85 sides so as to support tiny writes with reduced write amplifica‐
86 tion but expect only larger writes in subsequent allocation
87 units — where the exFAT bitmap would be placed by default.
88 Specifying --pack-bitmap attempts to avoid the potential prob‐
89 lems associated with issuing many small writes to the bitmap by
90 making it share an allocation unit with the FAT. If there is
91 insufficient space for the bitmap there, then this option will
92 have no effect, and the bitmap will be aligned at the boundary
93 as by default.
94 -q, --quiet
96 Prints only error messages while creating the exFAT filesystem.
97 -v, --verbose
99 Prints verbose debugging information while creating the exFAT
100 filesystem.
101 -V, --version
103 Prints the version number and exits.
104
106 mkfs(8), mount(8),
107 mkfs.exfat(8)