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
- -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. Suffixes of k, m, g, t, p, e may be specified to denote KiB, MiB, GiB, etc.
- -l, --length length
- Specifies the length of the allocation, in bytes. Suffixes of k, m, g, t, p, e may be specified to denote KiB, MiB, GiB, etc.
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-ng package and is
available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.