MAKEFS(8) FreeBSD System Manager's Manual MAKEFS(8)
NAME
makefs - create a file system image from a directory tree or a mtree
manifest
SYNOPSIS
makefs [-DxZ] [-B endian] [-b free-blocks] [-d debug-mask]
[-F mtree-specfile] [-f free-files] [-M minimum-size]
[-m maximum-size] [-N userdb-dir] [-O offset] [-o fs-options]
[-R roundup-size] [-S sector-size] [-s image-size] [-T timestamp]
[-t fs-type] image-file directory | manifest [extra-directory ...]
DESCRIPTION
The utility makefs creates a file system image into image-file from the
directory tree directory or from the mtree manifest manifest. If any
optional directory trees are passed in the extra-directory arguments,
then the directory tree of each argument will be merged into the
directory or manifest first before creating image-file. No special
devices or privileges are required to perform this task.
The options are as follows:
-B endian
Set the byte order of the image to endian. Valid byte orders are
`4321', `big', or `be' for big endian, and `1234', `little', or
`le' for little endian. Some file systems may have a fixed byte
order; in those cases this argument will be ignored.
-b free-blocks
Ensure that a minimum of free-blocks free blocks exist in the
image. An optional `%' suffix may be provided to indicate that
free-blocks indicates a percentage of the calculated image size.
-D Treat duplicate paths in an mtree manifest as warnings not error.
If this flag is specified more than once, warnings about duplicate
paths are not printed at all.
-d debug-mask
Enable various levels of debugging, depending upon which bits are
set in debug-mask. This option is intended for source debugging.
debug-mask is a bit map defined in the header file makefs.h. See
the source for usage, and look for defines starting with DEBUG_.
-F mtree-specfile
This is almost certainly not the option you are looking for. To
create an image from a list of files in an mtree format manifest,
specify it as the last argument on the command line, not as the
argument to -F.
Use mtree-specfile as an mtree(8) `specfile' specification. This
option has no effect when the image is created from a mtree
manifest rather than a directory.
If a specfile entry exists in the underlying file system, its
permissions and modification time will be used unless specifically
overridden by the specfile. An error will be raised if the type of
entry in the specfile conflicts with that of an existing entry.
In the opposite case (where a specfile entry does not have an entry
in the underlying file system) the following occurs: If the
specfile entry is marked optional, the specfile entry is ignored.
Otherwise, the entry will be created in the image, and it is
necessary to specify at least the following parameters in the
specfile: type, mode, gname, or gid, and uname or uid, and link (in
the case of symbolic links). If time is not provided, the current
time will be used. If flags is not provided, the current file
flags will be used. Missing regular file entries will be created
as zero-length files.
-f free-files
Ensure that a minimum of free-files free files (inodes) exist in
the image. An optional `%' suffix may be provided to indicate that
free-files indicates a percentage of the calculated image size.
-M minimum-size
Set the minimum size of the file system image to minimum-size.
-m maximum-size
Set the maximum size of the file system image to maximum-size. An
error will be raised if the target file system needs to be larger
than this to accommodate the provided directory tree.
-N userdb-dir
Use the user database text file master.passwd and group database
text file group from userdb-dir, rather than using the results from
the system's getpwnam(3) and getgrnam(3) (and related) library
calls.
-O offset
Instead of creating the filesystem at the beginning of the file,
start at offset. Valid only for ffs and msdos.
-o fs-options
Set file system specific options. fs-options is a comma separated
list of options. Valid file system specific options are detailed
below.
-p Deprecated. Create a sparse file for ffs. This is the same as the
preferred -Z flag.
-R roundup-size
Round the image up to roundup-size. roundup-size should be a
multiple of the file system block size. This option only applies
to the ffs file system type.
-S sector-size
Set the file system sector size to sector-size. Defaults to 512.
-s image-size
Set the size of the file system image to image-size. This is
equivalent to setting both the minimum (-M) and the maximum (-m)
sizes to the same value. For ffs and msdos the image-size does not
include the offset. offset is not included in that size.
-T timestamp
Specify a timestamp to be set for all filesystem files and
directories created so that repeatable builds are possible. The
timestamp can be a pathname, where the timestamps are derived from
that file, or an integer value interpreted as the number of seconds
from the Epoch. Timestamps in a mtree(5) specfile (specified with
-F) are used even if a default timestamp is specified. However,
the timestamps in an mtree manifest are ignored if a default
timestamp is specified.
-t fs-type
Create an fs-type file system image. The following file system
types are supported:
ffs BSD fast file system (default).
cd9660 ISO 9660 file system.
msdos FAT12, FAT16, or FAT32 file system.
zfs ZFS pool containing one or more file systems.
-x Exclude file system nodes not explicitly listed in the specfile.
-Z Create a sparse file for ffs. This is useful for virtual machine
images.
Where sizes are specified, a decimal number of bytes is expected. Two or
more numbers may be separated by an "x" to indicate a product. Each
number may have one of the following optional suffixes:
b Block; multiply by 512
k Kibi; multiply by 1024 (1 KiB)
m Mebi; multiply by 1048576 (1 MiB)
g Gibi; multiply by 1073741824 (1 GiB)
t Tebi; multiply by 1099511627776 (1 TiB)
w Word; multiply by the number of bytes in an integer
FFS-specific options
ffs images have ffs-specific optional parameters that may be provided.
Each of the options consists of a keyword, an equal sign (`='), and a
value. The following keywords are supported:
avgfilesize Expected average file size.
avgfpdir Expected number of files per directory.
bsize Block size.
density Bytes per inode. If unset, will allocate the minimum
number of inodes to represent the filesystem if no
free space has been requested (free blocks or minimum
size set); otherwise the larger of the newfs defaults
or what is required by the free inode parameters if
set.
fsize Fragment size.
label Label name of the image.
maxbpg Maximum blocks per file in a cylinder group.
minfree Minimum % free.
optimization Optimization preference; one of `space' or `time'.
extent Maximum extent size.
maxbpcg Maximum total number of blocks in a cylinder group.
version UFS version. 1 for FFS (default), 2 for UFS2.
softupdates 0 for disable (default), 1 for enable
CD9660-specific options
cd9660 images have ISO9660-specific optional parameters that may be
provided. The arguments consist of a keyword and, optionally, an equal
sign (`='), and a value. The following keywords are supported:
allow-deep-trees Allow the directory structure to exceed the
maximum specified in the spec.
allow-illegal-chars Allow illegal characters in filenames. This
option is not implemented.
allow-lowercase Allow lowercase characters in filenames.
This option is not implemented.
allow-max-name Allow 37 instead of 33 characters for
filenames by omitting the version id.
allow-multidot Allow multiple dots in a filename.
applicationid Application ID of the image.
bootimagedir Boot image directory. This option is not
implemented.
chrp-boot Write an MBR partition table to the image to
allow older CHRP hardware to boot.
boot-load-segment Set load segment for the boot image.
bootimage Filename of a boot image in the format
"sysid;filename", where "sysid" is one of
`efi', `i386', `mac68k', `macppc', or
`powerpc'.
generic-bootimage Load a generic boot image into the first 32K
of the cd9660 image.
hard-disk-boot Boot image is a hard disk image.
isolevel An integer representing the ISO 9660
interchange level where "level" is either `1'
or `2'. "level" `3' is not implemented.
keep-bad-images Do not discard images whose write was aborted
due to an error. For debugging purposes.
label Label name of the image.
no-boot Boot image is not bootable.
no-emul-boot Boot image is a "no emulation" ElTorito
image.
no-trailing-padding Do not pad the image (apparently Linux needs
the padding).
omit-trailing-period Omit trailing periods in filenames.
platformid Set platform ID of section header entry of
the boot image.
preparer Preparer ID of the image.
publisher Publisher ID of the image.
rockridge Use RockRidge extensions (for longer
filenames, etc.).
verbose Turns on verbose output.
volumeid Volume set identifier of the image.
msdos-specific options
msdos images have MS-DOS-specific optional parameters that may be
provided. The arguments consist of a keyword, an equal sign (`='), and a
value. The following keywords are supported (see newfs_msdos(8) for more
details):
backup_sector Location of the backup boot sector.
block_size Block size.
bootstrap Bootstrap file.
bytes_per_sector Bytes per sector.
create_size Create file size.
directory_entries Directory entries.
drive_heads Drive heads.
fat_type FAT type (12, 16, or 32).
floppy Preset drive parameters for standard format
floppy disks (160, 180, 320, 360, 640, 720,
1200, 1232, 1440, or 2880).
hidden_sectors Hidden sectors.
info_sector Location of the info sector.
media_descriptor Media descriptor.
num_FAT Number of FATs.
OEM_string OEM string.
offset Offset in device. This option will be
ignored if -O is set to a positive number.
reserved_sectors Reserved sectors.
sectors_per_cluster Sectors per cluster.
sectors_per_fat Sectors per FAT.
sectors_per_track Sectors per track.
size File System size.
volume_id Volume ID.
volume_label Volume Label.
zfs-specific options
The image created by makefs contains a ZFS pool with a single vdev of
type `disk'. The root dataset is always created implicitly and contains
the entire input directory tree unless additional datasets are specified
using the options described below.
To keep images reproducible, the pool GUID and other random identifiers
will always be the same across runs of makefs. This means that when a
pool is first imported, its GUID should be reset using zpool-reguid(8) to
avoid conflicting with other pools also generated by makefs; otherwise,
it will not be possible to import other pools. This can be configured
from /etc/rc.conf using the zpool_reguid variable.
The arguments consist of a keyword, an equal sign (`='), and a value.
The following keywords are supported:
ashift The base-2 logarithm of the minimum block
size. Typical values are 9 (512B blocks) and
12 (4KB blocks). The default value is 12.
bootfs The name of the bootable dataset for the
pool. Specifying this option causes the
`bootfs' property to be set in the created
pool.
mssize The size of metaslabs in the created pool.
By default, makefs allocates large (up to
512MB) metaslabs with the expectation that
the image will be auto-expanded upon first
use. This option allows the default
heuristic to be overridden.
verify-txgs Prompt OpenZFS to verify pool metadata during
import. This is disabled by default as it
may significantly increase import times.
poolguid Use the specified 64-bit integer as the pool
GUID. If this option is not specified, the
pool GUID will be random but fixed across
multiple identical invocations of makefs.
This option is useful for testing but not
required for reproducibility.
poolname The name of the ZFS pool. This option must
be specified.
rootpath An implicit path prefix added to dataset
mountpoints. By default it is /<poolname>.
For creating bootable pools, the rootpath
should be set to /. At least one dataset
must have a mountpoint equal to rootpath.
fs Create an additional dataset. This option
may be specified multiple times. The
argument value must be of the form
<dataset>[;<prop1=v1>[;<prop2=v2>[;...]]],
where dataset is the name of the dataset and
must belong to the pool's namespace. For
example, with a pool name of `test' all
dataset names must be prefixed by `test/'. A
dataset must exist at each level of the
pool's namespace. For example, to create
`test/foo/bar', `test/foo' must be created as
well.
The dataset mountpoints determine how the
datasets are populated with files from the
staged directory tree. Conceptually, all
datasets are mounted before any are populated
with files. The root of the staged directory
tree is mapped to rootpath.
Dataset properties, as described in
zfsprops(7), may be specified following the
dataset name. The following properties may
be set for a dataset:
atime
canmount
compression
exec
mountpoint
setuid
Note that makefs does not implement
compression of files included in the image,
regardless of the value of the compression
property.
SEE ALSO
mtree(5), rc.conf(5), zfsconcepts(7), zfsprops(7), zpoolprops(7),
mtree(8), newfs(8), zpool-reguid(8)
HISTORY
The makefs utility appeared in NetBSD 1.6. It was ported to FreeBSD and
first appeared in FreeBSD 8.0.
AUTHORS
Luke Mewburn <lukem@NetBSD.org> (original program),
Daniel Watt,
Walter Deignan,
Ryan Gabrys,
Alan Perez-Rathke,
Ram Vedam (cd9660 support),
Christos Zoulas (msdos support),
Mark Johnston (zfs support).
FreeBSD 15.1-STABLE-HBSD January 5, 2026 MAKEFS(8)