From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36626) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1da12F-000221-2n for qemu-devel@nongnu.org; Tue, 25 Jul 2017 10:42:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1da12D-00011x-5s for qemu-devel@nongnu.org; Tue, 25 Jul 2017 10:42:07 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:52305 helo=mx01.kamp.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1da12C-00010s-Sz for qemu-devel@nongnu.org; Tue, 25 Jul 2017 10:42:05 -0400 From: Peter Lieven Date: Tue, 25 Jul 2017 16:41:33 +0200 Message-Id: <1500993699-19299-5-git-send-email-pl@kamp.de> In-Reply-To: <1500993699-19299-1-git-send-email-pl@kamp.de> References: <1500993699-19299-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH V5 04/10] qemu-img: add documentation for compress settings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, lersek@redhat.com, den@openvz.org, mreitz@redhat.com, eblake@redhat.com, berrange@redhat.com, Peter Lieven Signed-off-by: Peter Lieven --- 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). +@item 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. + +@item 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. + +@item 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