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FALLOCATE(1)			 User Commands			  FALLOCATE(1)

NAME
       fallocate - preallocate or deallocate space to a file

SYNOPSIS
       fallocate [-n] [-p] [-o offset] -l length filename

DESCRIPTION
       fallocate  is  used  to manipulate the allocated disk space for a file,
       either to deallocate or preallocate it. For filesystems	which  support
       the  fallocate system call, preallocation is done quickly by allocating
       blocks and marking them as uninitialized, requiring no IO to  the  data
       blocks.	This  is  much	faster than creating a file by filling it with
       zeros.

       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.

OPTIONS
       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
       and YB.

       -n, --keep-size
	      Do  not modify the apparent length of the file.  This may effec‐
	      tively allocate blocks past EOF, which can  be  removed  with  a
	      truncate.

       -p, --punch-hole
	      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.

       -h, --help
	      Display help text and exit.

       -V, --version
	      Display version information and exit.

AUTHORS
       Eric Sandeen ⟨sandeen@redhat.com⟩
       Karel Zak ⟨kzak@redhat.com⟩

SEE ALSO
       fallocate(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/⟩.

util-linux			September 2011			  FALLOCATE(1)

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