NTFSFALLOCATE(8) System Manager's Manual NTFSFALLOCATE(8)
NAME
ntfsfallocate - preallocate space to a file on an NTFS volume
SYNOPSIS
ntfsfallocate [options] -l length device file [attr-type [attr-name]]
DESCRIPTION
ntfsfallocate preallocates space for any attribute of a file or direc-
tory, thus reserving space before actual contents is written. This is
similar to fallocate(1).
OPTIONS
Below is a summary of all the options that ntfsfallocate accepts.
Nearly all options have two equivalent names. The short name is pre-
ceded by - and the long name is preceded by --. Any single letter op-
tions, that don't take an argument, can be combined into a single com-
mand, e.g. -fv is equivalent to -f -v. Long named options can be ab-
breviated 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 pre-
allocate. 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 al-
located 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 de-
fault, 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 ntfsfallocate.
attr-type
Define a particular attribute type to be preallocated (advanced
use only). By default, the unnamed $DATA attribute (the contents
of a plain file) will be preallocated. The attribute has to be
specified by a number in decimal or hexadecimal :
┌────────────────────────────────────────────┐
│ Hex Decimal Name │
│ 0x10 16 "$STANDARD_INFORMATION" │
│ 0x20 32 "$ATTRIBUTE_LIST" │
│ 0x30 48 "$FILE_NAME" │
│ 0x40 64 "$OBJECT_ID" │
│ 0x50 80 "$SECURITY_DESCRIPTOR" │
│ 0x60 96 "$VOLUME_NAME" │
│ 0x70 112 "$VOLUME_INFORMATION" │
│ 0x80 128 "$DATA" │
│ 0x90 144 "$INDEX_ROOT" │
│ 0xA0 160 "$INDEX_ALLOCATION" │
│ 0xB0 176 "$BITMAP" │
│ 0xC0 192 "$REPARSE_POINT" │
│ 0xD0 208 "$EA_INFORMATION" │
│ 0xE0 224 "$EA" │
│ 0xF0 240 "$PROPERTY_SET" │
│ 0x100 256 "$LOGGED_UTILITY_STREAM" │
└────────────────────────────────────────────┘
attr-name
Define the name of the particular attribute type to be preallo-
cated (advanced use only).
EXAMPLES
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
BUGS
There are no known problems with ntfsfallocate, 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 describ-
ing the problem to the development team:
ntfs-3g-devel@lists.sf.net
AUTHORS
ntfsfallocate was written by Jean-Pierre Andre.
AVAILABILITY
ntfsfallocate is part of the ntfs-3g package and is available from:
https://github.com/tuxera/ntfs-3g/wiki/
SEE ALSO
ntfs-3g(8), ntfstruncate(8), ntfsprogs(8), fallocate(1)
ntfs-3g 2022.10.3 June 2014 NTFSFALLOCATE(8)
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