[Qemu-devel] [PATCH] qemu-img: document qed format on qemu-img man page

[Stefan Hajnoczi]

The qemu-img.1 man page is missing the qed format from its list of
supported formats.  Document the image creation options for qed.

Suggested-by: Michael Tokarev <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
When the qcow2 QED mode is merged we can update this again to reflect good
cache=writethrough performance in qcow2v3 /w QED mode.

 qemu-img.texi |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/qemu-img.texi b/qemu-img.texi
index 6fc3c28..78640a9 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -232,6 +232,28 @@ to grow.
 
 @end table
 
address@hidden 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.
+
+Supported options:
address@hidden @code
address@hidden backing_file
+File name of a base image (see @option{create} subcommand).
address@hidden 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.
address@hidden 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.
address@hidden 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.
address@hidden table
 
 @item qcow
 Old QEMU image format. Left for compatibility.
-- 
1.7.10