=head1 NAME

virt-format - Erase and make a blank disk

=head1 SYNOPSIS

 virt-format [--options] -a disk.img [-a disk.img ...]

=head1 DESCRIPTION

Virt-format takes an existing disk file (or it can be a host
partition, LV etc), B<erases all data on it>, and formats it as a
blank disk.  It can optionally create partition tables, empty
filesystems, logical volumes and more.

To create a disk containing data, you may be better to use
L<virt-make-fs(1)>.  If you are creating a blank disk to use in
L<guestfish(1)>, you should instead use the guestfish I<-N> option.

Normal usage would be something like this:

 virt-format -a disk.qcow

or this:

 virt-format -a /dev/VG/LV

F<disk.qcow> or F</dev/VG/LV> must exist already.  B<Any data on these
disks will be erased by these commands>.  These commands will create a
single empty partition covering the whole disk, with no filesystem
inside it.

Additional parameters can be used to control the creation of
partitions, filesystems, etc.  The most commonly used options are:

=over 4

=item B<--filesystem=[ext3|ntfs|vfat|...]>

Create an empty filesystem (C<ext3>, C<ntfs> etc) inside the partition.

=item B<--lvm[=/dev/VG/LV]>

Create a Linux LVM2 logical volume on the disk.  When used with
I<--filesystem>, the filesystem is created inside the LV.

=back

For more information about these and other options, see
L</OPTIONS> below.

The format of the disk is normally auto-detected, but you can also
force it by using the I<--format> option (q.v.).  In situations where
you do not trust the existing content of the disk, then it is
advisable to use this option to avoid possible exploits.

=head1 OPTIONS

=over 4

=item B<--help>

Display brief help.

=item B<-a> file

=item B<--add> file

Add I<file>, a disk image, host partition, LV, external USB disk, etc.

The format of the disk image is auto-detected.  To override this and
force a particular format use the I<--format=..> option.

B<Any existing data on the disk is erased.>

=item B<-a> URI

=item B<--add> URI

Add a remote disk.  See L<guestfish(1)/ADDING REMOTE STORAGE>.

=item B<--filesystem=ext3|ntfs|vfat|...>

Create an empty filesystem of the specified type.  Many filesystem
types are supported by libguestfs.

=item B<--filesystem=none>

Create no filesystem.  This is the default.

=item B<--format=raw|qcow2|..>

=item B<--format>

The default for the I<-a> option is to auto-detect the format of the
disk image.  Using this forces the disk format for I<-a> options which
follow on the command line.  Using I<--format> with no argument
switches back to auto-detection for subsequent I<-a> options.

For example:

 virt-format --format=raw -a disk.img

forces raw format (no auto-detection) for F<disk.img>.

 virt-format --format=raw -a disk.img --format -a another.img

forces raw format (no auto-detection) for F<disk.img> and reverts to
auto-detection for F<another.img>.

If you have untrusted raw-format guest disk images, you should use
this option to specify the disk format.  This avoids a possible
security problem with malicious guests (CVE-2010-3851).

=item B<--label=>LABEL

Set the filesystem label.

=item B<--lvm=/dev/I<VG>/I<LV>>

Create a Linux LVM2 logical volume called F</dev/I<VG>/I<LV>>.  You
can change the name of the volume group and logical volume.

=item B<--lvm>

Create a Linux LVM2 logical volume with the default name
(F</dev/VG/LV>).

=item B<--lvm=none>

Create no logical volume.  This is the default.

=item B<--partition>

Create either an MBR or GPT partition covering the whole disk.  MBR is
chosen if the disk size is E<lt> 2 TB, GPT if E<ge> 2 TB.

This is the default.

=item B<--partition=gpt>

Create a GPT partition.

=item B<--partition=mbr>

Create an MBR partition.

=item B<--partition=none>

Create no partition table.  Note that Windows may not be able to see
these disks.

=item B<-v>

=item B<--verbose>

Enable verbose messages for debugging.

=item B<-V>

=item B<--version>

Display version number and exit.

=item B<--wipe>

Normally virt-format does not wipe data from the disk (because that
takes a long time).  Thus if there is data on the disk, it is only
hidden and partially overwritten by virt-format, and it might be
recovered by disk editing tools.

If you use this option, virt-format writes zeroes over the whole disk
so that previous data is not recoverable.

=item B<-x>

Enable tracing of libguestfs API calls.

=back

=head1 EXIT STATUS

This program returns C<0> on success, or C<1> on failure.

=head1 SEE ALSO

L<guestfs(3)>,
L<guestfish(1)>,
L<virt-filesystems(1)>,
L<virt-make-fs(1)>,
L<virt-rescue(1)>,
L<virt-resize(1)>,
L<http://libguestfs.org/>.

=head1 AUTHOR

Richard W.M. Jones L<http://people.redhat.com/~rjones/>

=head1 COPYRIGHT

Copyright (C) 2012 Red Hat Inc.
