From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1G0GRa-0000ZZ-0P for qemu-devel@nongnu.org; Tue, 11 Jul 2006 07:30:22 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1G0GRY-0000ZE-L3 for qemu-devel@nongnu.org; Tue, 11 Jul 2006 07:30:20 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1G0GRY-0000ZA-Hc for qemu-devel@nongnu.org; Tue, 11 Jul 2006 07:30:20 -0400 Received: from [64.233.182.188] (helo=nf-out-0910.google.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1G0GSr-00081d-5a for qemu-devel@nongnu.org; Tue, 11 Jul 2006 07:31:41 -0400 Received: by nf-out-0910.google.com with SMTP id a25so951001nfc for ; Tue, 11 Jul 2006 04:30:18 -0700 (PDT) Message-ID: <46d6db660607110430w74fa175avc0f01a52bb91f44a@mail.gmail.com> Date: Tue, 11 Jul 2006 13:30:18 +0200 From: "Christian MICHON" Subject: Re: [Qemu-devel] QCow v2 In-Reply-To: <47604893-CBC5-4EF2-B048-00DA701301A3@claunia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <1151981142.5476.13.camel@localhost.localdomain> <44AA33AD.3030300@bellard.org> <46d6db660607040344i7bc7e4cbx83fc424a6ebefa8a@mail.gmail.com> <44AA4D74.9070005@dblab.ece.ntua.gr> <46d6db660607040651y3ad5391bwfbe40776ea7ecd0@mail.gmail.com> <47604893-CBC5-4EF2-B048-00DA701301A3@claunia.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org ok, I did this experiment (long and painful). a XP2003/SP1 qemu guest required 964,231,168 bytes qcow image. zlib qcow image became 459,686,368 bytes. lzma estimation (4k clusters) is 437,038,838 bytes. Yes, 5% are still gained, but the time to get the lzma'ed qcow is disastrous (especially on systems with anti-virus and anti-malware). Do you still think it's worth it ? On 7/4/06, Natalia Portillo wrote: > Just there is a question: > > If improvement is 5%, IS NOT THE SAME with a 5Mb HDD that with a 5Gb > HDD. > > Wanna do testing with more real scenarios? > > Like a Windows XP full installation for example? > > I'm very sure that there will be a real difference. > > Regards > > El 04/07/2006, a las 15:51, Christian MICHON escribi=F3: > > > for what it's worth: > > qcow with "lzo -9" would become 4155352 bytes (bigger than original > > zlib qcow). > > > > yet it's true at the compression and decompression stages that it > > feels faster... > > > > On 7/4/06, Elefterios Stamatogiannakis > > wrote: > >> I agree > >> > >> Lzma and zlib are pretty much equivalent, so there is pretty much > >> nothing to be gained except slightly more compression. > >> > >> On the other hand with lzo (1) there would be quite a considerable > >> speed > >> improvement at the cost of compression. > >> > >> It could also mean that reading on the qcow format could some > >> times be > >> faster (with compressible data) than reading directly from the > >> hard disk. > >> > >> lefteris > >> > >> (1) http://www.oberhumer.com/opensource/lzo/ > >> > >> Johannes Schindelin wrote: > >> > Hi, > >> > > >> > On Tue, 4 Jul 2006, Christian MICHON wrote: > >> > > >> >> how about also adding lzma compression for qcow ? > >> > > >> > Why lzma? We already have a dependency on zlib, why not just > >> take that? > >> > > >> > Ciao, > >> > Dscho > >> > > >> > > >> > _______________________________________________ > >> > Qemu-devel mailing list > >> > Qemu-devel@nongnu.org > >> > http://lists.nongnu.org/mailman/listinfo/qemu-devel > >> > >> > >> _______________________________________________ > >> Qemu-devel mailing list > >> Qemu-devel@nongnu.org > >> http://lists.nongnu.org/mailman/listinfo/qemu-devel > >> > > > > > > -- > > Christian > > > > > > _______________________________________________ > > Qemu-devel mailing list > > Qemu-devel@nongnu.org > > http://lists.nongnu.org/mailman/listinfo/qemu-devel > > > > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel > --=20 Christian