.Dd February 2, 2015
.Dt FALLOCATE 1
.Os ubase
.Sh NAME
.Nm fallocate
.Nd preallocate blocks to a file
.Sh SYNOPSIS
.Nm
.Op Fl o Ar offset
.Fl l Ar length Ar file
.Sh DESCRIPTION
.Nm
preallocates blocks to a file. Only certain filesystems support the
.Xr fallocate 2
system call.  This is a very fast operation to allocate uninitialized blocks
in a file without doing any IO. As of the Linux kernel v2.6.31, the
.Xr fallocate 2
system call is supported by the btrfs, ext4, ocfs2, and xfs filesystems.
.Sh OPTIONS
.Bl -tag -width Ds
.It Fl l Ar length
Specifies the length of the allocation, in bytes.
.It Fl o
Specifies the beginning offset of the allocation, in bytes.
.El
.Sh SEE ALSO
.Xr fallocate 2