1NTFSFALLOCATE(8) System Manager's Manual NTFSFALLOCATE(8)
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6 ntfsfallocate - preallocate space to a file on an NTFS volume
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9 ntfsfallocate [options] -l length device file [attr-type [attr-name]]
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12 ntfsfallocate preallocates space for any attribute of a file or direc‐
13 tory, thus reserving space before actual contents is written. This is
14 similar to fallocate(1).
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17 Below is a summary of all the options that ntfsfallocate accepts.
18 Nearly all options have two equivalent names. The short name is pre‐
19 ceded by - and the long name is preceded by --. Any single letter op‐
20 tions, that don't take an argument, can be combined into a single com‐
21 mand, e.g. -fv is equivalent to -f -v. Long named options can be ab‐
22 breviated to any unique prefix of their name.
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24 -f, --force
25 This will override some sensible defaults, such as not using a
26 mounted volume. Use this option with caution.
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28 -h, --help
29 Show a list of options with a brief description of each one.
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31 -l, --length LENGTH
32 This is a mandatory option to specify the number of bytes to
33 preallocate. It will be rounded up to a multiple of the cluster
34 size. A suffix of K, M, G, T, P or E may be appended to mean a
35 multiplicative factor of a power of 1000. Similarly a suffix of
36 Ki, Mi, Gi, Ti, Pi or Ei may be appended to mean a multiplica‐
37 tive factor of a power of 1024.
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39 -n, --no-size-change
40 Do not change the apparent size of the file. The space allocated
41 beyond the apparent size is not zeroed, but subsequent writing
42 beyond the apparent end of file will force zeroing the inner al‐
43 located space as it cannot be considered as a hole any more, and
44 this may take significant time.
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46 -N, --no-action
47 Simulate the allocation without actually write to device.
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49 -o, --offset OFFSET
50 Specify the offset in the file where preallocation starts. By
51 default, the preallocation is counted from the beginning of the
52 file. Space already allocated in the area defined by offset and
53 length is preserved.
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55 -q, --quiet
56 Suppress some debug/warning/error messages.
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58 -v, --verbose
59 Display more debug/warning/error messages.
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61 -V, --version
62 Show the version number, copyright and license of ntfsfallocate.
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64 attr-type
65 Define a particular attribute type to be preallocated (advanced
66 use only). By default, the unnamed $DATA attribute (the con‐
67 tents of a plain file) will be preallocated. The attribute has
68 to be specified by a number in decimal or hexadecimal :
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70 ┌───────────────────────────────────────────┐
71 │Hex Decimal Name │
72 │0x10 16 "$STANDARD_INFORMATION" │
73 │0x20 32 "$ATTRIBUTE_LIST" │
74 │0x30 48 "$FILE_NAME" │
75 │0x40 64 "$OBJECT_ID" │
76 │0x50 80 "$SECURITY_DESCRIPTOR" │
77 │0x60 96 "$VOLUME_NAME" │
78 │0x70 112 "$VOLUME_INFORMATION" │
79 │0x80 128 "$DATA" │
80 │0x90 144 "$INDEX_ROOT" │
81 │0xA0 160 "$INDEX_ALLOCATION" │
82 │0xB0 176 "$BITMAP" │
83 │0xC0 192 "$REPARSE_POINT" │
84 │0xD0 208 "$EA_INFORMATION" │
85 │0xE0 224 "$EA" │
86 │0xF0 240 "$PROPERTY_SET" │
87 │0x100 256 "$LOGGED_UTILITY_STREAM" │
88 └───────────────────────────────────────────┘
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90 attr-name
91 Define the name of the particular attribute type to be preallo‐
92 cated (advanced use only).
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95 Preallocate 100MB to the file database.db located in the Data directory
96 which is at the root of an NTFS file system.
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98 ntfsfallocate -l 100M /dev/sda1 Data/database.db
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102 There are no known problems with ntfsfallocate, however it can lead to
103 configurations not supported by Windows and Windows may crash (BSOD)
104 when writing to preallocated clusters which were not written to ear‐
105 lier. Files with preallocated space should be fully be written to be‐
106 fore they are updated by Windows.
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108 If you find a bug in ntfsfallocate proper, please send an email de‐
109 scribing the problem to the development team:
110 ntfs-3g-devel@lists.sf.net
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113 ntfsfallocate was written by Jean-Pierre Andre.
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116 ntfsfallocate is part of the ntfs-3g package and is available from:
117 https://github.com/tuxera/ntfs-3g/wiki/
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120 ntfs-3g(8), ntfstruncate(8), ntfsprogs(8), fallocate(1)
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124ntfs-3g 2022.10.3 June 2014 NTFSFALLOCATE(8)