| .TH mkfs.exfat 8 |
| .SH NAME |
| mkfs.exfat \- create an exFAT filesystem |
| .SH SYNOPSIS |
| .B mkfs.exfat |
| [ |
| .B \-b |
| .I boundary_alignment |
| ] [ |
| .B \-c |
| .I cluster_size |
| ] [ |
| .B \-f |
| ] [ |
| .B \-h |
| ] [ |
| .B \-L |
| .I volume_label |
| ] [ |
| .B \-\-pack\-bitmap |
| ] [ |
| .B \-v |
| ] |
| .I device |
| .br |
| .B mkfs.exfat \-V |
| .SH DESCRIPTION |
| .B 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 |
| .BR mkfs (8) |
| when it is given the |
| .B \-t exfat |
| option. |
| .PP |
| As an example, to make a filesystem on the first partition on the first |
| SCSI disk, use: |
| .IP |
| .B mkfs.exfat /dev/sda1 |
| .PP |
| .SH OPTIONS |
| .TP |
| .BR \-b ", " \-\-boundary\-align =\fIalignment\fR |
| Specifies the alignment for the FAT and the start of the cluster heap. |
| The \fIalignment\fR argument is specified in bytes or may be specified with |
| \fBm\fR/\fBM\fR suffix for mebibytes or \fBk\fR/\fBK\fR 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 \fIalignment\fR 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. |
| .\" source: SD Specifications Part 2: File System Specification Version 3.00 |
| .TS |
| center; |
| cb1s6cbcb,nnnn. |
| 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 |
| .TE |
| .TP |
| .BR \-c ", " \-\-cluster\-size =\fIsize\fR |
| Specifies the cluster size of the exFAT file system. |
| The \fIsize\fR argument is specified in bytes or may be specified with |
| \fBm\fR/\fBM\fR suffix for mebibytes or \fBk\fR/\fBK\fR suffix for kibibytes |
| and must be a power of two. |
| .TP |
| .BR \-f ", " \-\-full\-format |
| Performs a full format. |
| This zeros the entire disk device while creating the exFAT filesystem. |
| .TP |
| .BR \-h ", " \-\-help |
| Prints the help and exit. |
| .TP |
| .BR \-L ", " \-\-volume\-label =\fIlabel\fR |
| Specifies the volume label to be associated with the exFAT filesystem. |
| .TP |
| .B \-\-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 \[em] where the exFAT bitmap would be placed by default. |
| Specifying \fB\-\-pack\-bitmap\fR 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. |
| .TP |
| .BR \-v ", " \-\-verbose |
| Prints verbose debugging information while creating the exFAT filesystem. |
| .TP |
| .BR \-V ", " \-\-version |
| Prints the version number and exits. |
| .SH SEE ALSO |
| .BR mkfs (8), |
| .BR mount (8), |