FALLOCATE(1) User Commands FALLOCATE(1)NAMEfallocate - preallocate space to a file
SYNOPSISfallocate [-n] [-p] [-o offset] -l length filename
DESCRIPTIONfallocate is used to preallocate blocks to a file. For filesystems
which support the fallocate system call, this is done quickly by allo‐
cating blocks and marking them as uninitialized, requiring no IO to the
data blocks. This is much faster than creating a file by filling it
As of the Linux Kernel v2.6.31, the fallocate system call is supported
by the btrfs, ext4, ocfs2, and xfs filesystems.
The exit code returned by fallocate is 0 on success and 1 on failure.
The length and offset arguments may be followed by the multiplicative
suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB
and YiB (the "iB" is optional, e.g. "K" has the same meaning as "KiB")
or the suffixes KB=1000, MB=1000*1000, and so on for GB, TB, PB, EB, ZB
Do not modify the apparent length of the file. This may effec‐
tively allocate blocks past EOF, which can be removed with a
Punch holes in the file, the range should not exceed the length
of the file.
-o, --offset offset
Specifies the beginning offset of the allocation, in bytes.
-l, --length length
Specifies the length of the allocation, in bytes.
Display help text and exit.
Display version information and exit.
Eric Sandeen ⟨email@example.com⟩
Karel Zak ⟨firstname.lastname@example.org⟩
SEE ALSOfallocate(2), posix_fallocate(3), truncate(1)AVAILABILITY
The fallocate command is part of the util-linux package and is avail‐
able from Linux Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils
util-linux September 2011 FALLOCATE(1)