FALLOCATE(1)                                                                                                        FALLOCATE(1)



NAME
       fallocate - preallocate space to a file.

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

DESCRIPTION
       fallocate is used to preallocate blocks to a file.  For filesystems which support the fallocate system call, this 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 binary (2^N) suffixes KiB, MiB, GiB, TiB, PiB and EiB (the "iB" is
       optional, e.g. "K" has the same meaning as "KiB") or decimal (10^N) suffixes KB, MB, GB, PB and EB.

       -h, --help
              Print help and exit.

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

       -o, --offset offset
              Specifies the beginning offset of the allocation, in bytes.

       -l, --length length
              Specifies the length of the allocation, in bytes.

AUTHORS
       Eric Sandeen <sandeenATredhat.com>
       Karel Zak <kzakATredhat.com>

SEE ALSO
       fallocate(2), posix_fallocate(3), truncate(1)

AVAILABILITY
       The   fallocate   command   is   part   of   the   util-linux-ng   package   and   is   available   from   ftp://ftp.ker-
       nel.org/pub/linux/utils/util-linux-ng/.




Version 1.0                                                 Jul 2009                                                FALLOCATE(1)