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 <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   available   from
       ftp://ftp.kernel.org/pub/linux/utils/util-linux/.