diff options
authorStefan Hajnoczi <>2012-06-13 14:29:15 +0100
committerMichael Roth <>2012-06-25 09:04:33 -0500
commit845685265756467050859e2359acf16321111352 (patch)
parentvirtio: Fix compiler warning for non Linux hosts (diff)
qemu-img: document qed format on qemu-img man page
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 <> Signed-off-by: Stefan Hajnoczi <> Signed-off-by: Kevin Wolf <> (cherry picked from commit f085800e245836fed27fddb3b624a29326637657) Signed-off-by: Michael Roth <>
1 files changed, 23 insertions, 0 deletions
diff --git a/qemu-img.texi b/qemu-img.texi
index 6fc3c28e0..9cee2eaa6 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -232,6 +232,29 @@ 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.