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[Qemu-devel] [PATCH V5 04/10] qemu-img: add documentation for compress s
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH V5 04/10] qemu-img: add documentation for compress settings |
Date: |
Tue, 25 Jul 2017 16:41:33 +0200 |
Signed-off-by: Peter Lieven <address@hidden>
---
qemu-img.texi | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/qemu-img.texi b/qemu-img.texi
index 72dabd6..3612c59 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -676,6 +676,32 @@ file which is COW and has data blocks already, it couldn't
be changed to NOCOW
by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
the NOCOW flag is set or not (Capital 'C' is NOCOW flag).
address@hidden compress.format
+Defines which compression algorithm is should be used for compressed clusters.
+The following options are available if support for the respective libraries
+has been enabled at compile time:
+
+ deflate Uses standard zlib defalte compression
+
+The compression algorithm can only be defined at image create time and cannot
+be changed later.
+
+Note: defining compression format settings which are different from the old
+ default (format=deflate, level=0, window-size=12) will result in the
+ compression format extension being written to the Qcow2 image. Versions
+ of QEMU before 2.11 will not be able to open images with this extension.
+
address@hidden compress.level
+Valid for compress.format=deflate defines the compression level to use for
+selected compression format. The default of @code{compress.level=0} will use
+the default compression level for the format. Alternate values range from 1 for
+fastest compression to 9 for the best compression.
+
address@hidden compress.window-size
+Valid for compress.format=deflate defines the compression window size used
+during compression. Valid window sizes for deflate compression range from 8 to
+15 inclusively. The default is @code{compress.window-size=15}.
+
@end table
@item Other
--
1.9.1
- [Qemu-devel] [PATCH V5 06/10] block/qcow2: simplify ret usage in qcow2_create, (continued)
- [Qemu-devel] [PATCH V5 06/10] block/qcow2: simplify ret usage in qcow2_create, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 02/10] qapi/block-core: add Qcow2Compress parameters, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 09/10] block/qcow2: add lzo compress format, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 10/10] block/qcow2: add compress info to image specific info, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 07/10] block/qcow2: optimize qcow2_co_pwritev_compressed, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 08/10] block/qcow2: start using the compress format extension, Peter Lieven, 2017/07/25
- [Qemu-devel] [PATCH V5 04/10] qemu-img: add documentation for compress settings,
Peter Lieven <=
- [Qemu-devel] [PATCH V5 05/10] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/25