From 9de27607666aedb376e4bfeeae4c6d9903bef9a8 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 2 Mar 2012 16:28:20 +0100 Subject: [PATCH 09/12] Documentation: Add qemu-img check/rebase RH-Author: Kevin Wolf Message-id: <1330705703-8967-2-git-send-email-kwolf@redhat.com> Patchwork-id: 37892 O-Subject: [RHEL-6.3 qemu-kvm PATCH 1/4] Documentation: Add qemu-img check/rebase Bugzilla: 725748 RH-Acked-by: Ademar de Souza Reis Jr. RH-Acked-by: Markus Armbruster RH-Acked-by: Luiz Capitulino Bugzilla: 725748 Signed-off-by: Kevin Wolf (cherry picked from commit e61846908efd5ea0916d157a82adabf0674a01b0) --- qemu-img.texi | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-) Signed-off-by: Michal Novotny --- qemu-img.texi | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-) diff --git a/qemu-img.texi b/qemu-img.texi index 8eca18b..ce53411 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -66,6 +66,13 @@ lists all snapshots in the given image Command description: @table @option +@item check [-f @var{fmt}] @var{filename} + +Perform a consistency check on the disk image @var{filename}. + +Only the formats @code{qcow2}, @code{qed} and @code{vdi} support +consistency checks. + @item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}] Create the new disk image @var{filename} of size @var{size} and format @@ -114,6 +121,40 @@ they are displayed too. List, apply, create or delete snapshots in image @var{filename}. +@item rebase [-f @var{fmt}] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename} + +Changes the backing file of an image. Only the formats @code{qcow2} and +@code{qed} support changing the backing file. + +The backing file is changed to @var{backing_file} and (if the image format of +@var{filename} supports this) the backing file format is changed to +@var{backing_fmt}. + +There are two different modes in which @code{rebase} can operate: +@table @option +@item Safe mode +This is the default mode and performs a real rebase operation. The new backing +file may differ from the old one and qemu-img rebase will take care of keeping +the guest-visible content of @var{filename} unchanged. + +In order to achieve this, any clusters that differ between @var{backing_file} +and the old backing file of @var{filename} are merged into @var{filename} +before actually changing the backing file. + +Note that the safe mode is an expensive operation, comparable to converting +an image. It only works if the old backing file still exists. + +@item Unsafe mode +qemu-img uses the unsafe mode if @code{-u} is specified. In this mode, only the +backing file name and format of @var{filename} is changed without any checks +on the file contents. The user must take care of specifying the correct new +backing file, or the guest-visible content of the image will be corrupted. + +This mode is useful for renaming or moving the backing file to somewhere else. +It can be used without an accessible old backing file, i.e. you can use it to +fix an image whose backing file has already been moved/renamed. +@end table + @item resize @var{filename} [+ | -]@var{size} Change the disk image as if it had been created with @var{size}. -- 1.7.7.6