From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
To: qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Subject: [Qemu-devel] [PATCH v2] qemu-img: document qed format on qemu-img man page
Date: Wed, 13 Jun 2012 14:29:15 +0100 [thread overview]
Message-ID: <1339594155-9783-1-git-send-email-stefanha@linux.vnet.ibm.com> (raw)
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 <mjt@tls.msk.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
v2:
* Add mention of cache=directsync [Kevin]
* Mention qcow2 [Kevin]
qemu-img.texi | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/qemu-img.texi b/qemu-img.texi
index 6fc3c28..9cee2ea 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.
--
1.7.10
next reply other threads:[~2012-06-13 13:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-13 13:29 Stefan Hajnoczi [this message]
2012-06-13 15:40 ` [Qemu-devel] [PATCH v2] qemu-img: document qed format on qemu-img man page Kevin Wolf
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