Provided by: util-linux_2.20.1-1ubuntu3_i386 bug


       fallocate - preallocate space to a file


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


       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.


       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.


       Eric Sandeen <>
       Karel Zak <>


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


       The  fallocate  command  is  part  of  the  util-linux  package  and is
       available from