Section: Maintenance Commands (8)
Updated: June 2014Index
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ntfsfallocate - preallocate space to a file on an NTFS volume
] -l length device file [attr-type
preallocates space for any attribute of a file or directory, thus reserving
space before actual contents is written. This is similar to fallocate
Below is a summary of all the options that
accepts. Nearly all options have two equivalent names. The short name is
and the long name is preceded by
Any single letter options, that don't take an argument, can be combined into a
single command, e.g.
is equivalent to
Long named options can be abbreviated to any unique prefix of their name.
- -f, --force
This will override some sensible defaults, such as not using a mounted volume.
Use this option with caution.
- -h, --help
Show a list of options with a brief description of each one.
- -l, --length LENGTH
This is a mandatory option to specify the number of bytes to preallocate.
It will be rounded up to a multiple of the cluster size.
A suffix of K, M, G, T, P or E may be appended to
mean a multiplicative factor of a power of 1000. Similarly a suffix of
Ki, Mi, Gi, Ti, Pi or Ei may be appended to mean a multiplicative factor
of a power of 1024.
- -n, --no-size-change
Do not change the apparent size of the file. The space allocated beyond
the apparent size is not zeroed, but subsequent writing beyond the apparent
end of file will force zeroing the inner allocated space as it cannot be
considered as a hole any more, and this may take significant time.
- -N, --no-action
Simulate the allocation without actually write to device.
- -o, --offset OFFSET
Specify the offset in the file where preallocation starts. By default,
the preallocation is counted from the beginning of the file. Space already
allocated in the area defined by offset and length is preserved.
- -q, --quiet
Suppress some debug/warning/error messages.
- -v, --verbose
Display more debug/warning/error messages.
- -V, --version
Show the version number, copyright and license of
Define a particular attribute type to be preallocated (advanced use only).
By default, the unnamed $DATA attribute (the contents of a plain file) will
be preallocated. The attribute has to be specified by a number in decimal
or hexadecimal :
Define the name of the particular attribute type to be preallocated
(advanced use only).
Preallocate 100MB to the file database.db located in the Data directory
which is at the root of an NTFS file system.
ntfsfallocate -l 100M /dev/sda1 Data/database.db
There are no known problems with
however it can lead to configurations not supported by Windows
and Windows may crash (BSOD) when writing to preallocated clusters
which were not written to earlier. Files with preallocated space should
be fully be written to before they are updated by Windows.
If you find a bug in ntfsfallocate proper, please send an email
describing the problem to the development team:
was written by Jean-Pierre Andre.
is part of the
package and is available from:
- SEE ALSO