debvm-create: update documentation for --skip=ext4

1 files changed, 7 insertions, 1 deletions

diff --git a/bin/debvm-create b/bin/debvm-create
index 4651e00..41a6139 100755
--- a/bin/debvm-create
+++ b/bin/debvm-create
@@ -15,7 +15,7 @@ B<debvm-create> [B<-a> I<architecture>] [B<-h> I<hostname>] [B<-k> F<sshkey>] [B
 
 =head1 DESCRIPTION
 
-B<debvm-create> is essentially a thin wrapper around B<mmdebstrap> for creating a raw ext4 or tar filesystem image for booting with B<debvm-run>.
+B<debvm-create> is essentially a thin wrapper around B<mmdebstrap> for creating a raw ext4 filesystem image for booting with B<debvm-run>.
 The purpose of these images primarily is testing the different releases and architectures without access to a physical machine of that architecture.
 Beyond essential packages, the image will contain B<apt>, an init system and a suitable kernel package.
 Notably absent is a bootloader and a partition table.
@@ -69,6 +69,12 @@ Skips adding a the customize-autologin.sh to B<mmdebstrap> that configures
 automatic root login on a serial console and also parses the C<TERM> kernel
 cmdline and passes it as C<TERM> to B<agetty>.
 
+=item B<ext4>
+
+Internally, B<mmdebstrap> creates a tar archive first and converts that to ext2, which is then upgraded to ext4.
+This option causes the conversion to ext2 and further steps to be skipped and the output image will be a tar archive instead.
+Such a tar archive is not suitable for being booted by B<debvm-run>.
+
 =item B<kernel>
 
 skips installing a linux kernel image.