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 <[EMAIL PROTECTED]> 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 escribió: > 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 <[EMAIL PROTECTED]> > 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
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