qapi schema: add Netdev types

[qemu.git] / qemu-img.texi

diff --git a/qemu-img.texi b/qemu-img.texi
index 526474c112f0761b7e8eef2ad6ba2bbf3fcdb470..77c6d0b6b0cb7e6e295d974b505e3d0397de520d 100644 (file)
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -38,6 +38,17 @@ by the used format or see the format descriptions below for details.
 indicates that target image must be compressed (qcow format only)
 @item -h
 with or without a command shows help and lists the supported formats
+@item -p
+display progress bar (convert and rebase commands only)
+@item -S @var{size}
+indicates the consecutive number of bytes that must contain only zeros
+for qemu-img to create a sparse image during conversion. This value is rounded
+down to the nearest 512 bytes. You may use the common size suffixes like
+@code{k} for kilobytes.
+@item -t @var{cache}
+specifies the cache mode that should be used with the (destination) file. See
+the documentation of the emulator's @code{-drive cache=...} option for allowed
+values.
 @end table
 
 Parameters to snapshot subcommand:
@@ -59,10 +70,15 @@ lists all snapshots in the given image
 Command description:
 
 @table @option
-@item check [-f @var{fmt}] @var{filename}
+@item check [-f @var{fmt}] [-r [leaks | all]] @var{filename}
 
 Perform a consistency check on the disk image @var{filename}.
 
+If @code{-r} is specified, qemu-img tries to repair any inconsistencies found
+during the check. @code{-r leaks} repairs only cluster leaks, whereas
+@code{-r all} fixes all kinds of errors, with a higher risk of choosing the
+wrong fix or hiding corruption that has already occured.
+
 Only the formats @code{qcow2}, @code{qed} and @code{vdi} support
 consistency checks.
 
@@ -80,11 +96,11 @@ this case. @var{backing_file} will never be modified unless you use the
 The size can also be specified using the @var{size} option with @code{-o},
 it doesn't need to be specified separately in this case.
 
-@item commit [-f @var{fmt}] @var{filename}
+@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
 
 Commit the changes recorded in @var{filename} in its base image.
 
-@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] @var{filename} [@var{filename2} [...]] @var{output_filename}
+@item convert [-c] [-p] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
 
 Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}
 using format @var{output_fmt}. It can be optionally compressed (@code{-c}
@@ -114,7 +130,7 @@ 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}
+@item rebase [-f @var{fmt}] [-t @var{cache}] [-p] [-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.
@@ -148,6 +164,24 @@ 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
 
+You can use @code{rebase} to perform a ``diff'' operation on two
+disk images.  This can be useful when you have copied or cloned
+a guest, and you want to get back to a thin image on top of a
+template or base image.
+
+Say that @code{base.img} has been cloned as @code{modified.img} by
+copying it, and that the @code{modified.img} guest has run so there
+are now some changes compared to @code{base.img}.  To construct a thin
+image called @code{diff.qcow2} that contains just the differences, do:
+
+@example
+qemu-img create -f qcow2 -b modified.img diff.qcow2
+qemu-img rebase -b base.img diff.qcow2
+@end example
+
+At this point, @code{modified.img} can be discarded, since
+@code{base.img + diff.qcow2} contains the same information.
+
 @item resize @var{filename} [+ | -]@var{size}
 
 Change the disk image as if it had been created with @var{size}.
@@ -203,6 +237,29 @@ to grow.
 
 @end table
 
+@item qed
+Image format with support for backing files and compact image files (when your
+filesystem or transport medium does not support holes).  Good performance due
+to less metadata than the more featureful qcow2 format, especially with
+cache=writethrough or cache=directsync.  Consider using qcow2 which will soon
+have a similar optimization and is most actively developed.
+
+Supported options:
+@table @code
+@item backing_file
+File name of a base image (see @option{create} subcommand).
+@item backing_fmt
+Image file format of backing file (optional).  Useful if the format cannot be
+autodetected because it has no header, like some vhd/vpc files.
+@item cluster_size
+Changes the cluster size (must be power-of-2 between 4K and 64K). Smaller
+cluster sizes can improve the image file size whereas larger cluster sizes
+generally provide better performance.
+@item table_size
+Changes the number of clusters per L1/L2 table (must be power-of-2 between 1
+and 16).  There is normally no need to change this value but this option can be
+used for performance benchmarking.
+@end table
 
 @item qcow
 Old QEMU image format. Left for compatibility.