Hi everybody, I am searching for a copy-on-write solution for Xen and tested blktap2 with the vhd backend. My Test: I''ve created a master-image with "dd" and installed WindowsXP on the image. Then I used vhd-util to create a copy-on-write-image for the master-image. After booting the VM and logging in the, the cow-image had a size of 260 MB. That''s a little bit weird, because I didn''t really changend any data. Afterwards I downloaded eclipse in the VM, to see how big the overhead is. The eclipse zip-file is 190.64 MB big. But the cow-image had a size of 1468.29 MB after downloading eclipse. That''s an overhead of 670 %. Then I unpacked eclipse. So that the actual change in the VM had 425.37 MB. At that moment the cow-image was 1979.79 MB big. The result is 365 % Overhead, that''s better then the result before, but still not very good. My questions are: Have I done anything wrong at measuring the overhead? Is there a bug in blktap2/vhd? Or is this a usual result? Here the configuration: The host is a Xen 4.0 (I compiled it myself) on an 2.6.32-xen-amd64 debian kernel (also self compiled to include some mudules statically). The guest is a WindowsXP 32 bit SP2. I would appreciate your help on that very much. Bastian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Am Mittwoch, 23. Juni 2010, 17:26:05 schrieb Bastian de Groot:> Hi everybody, > > I am searching for a copy-on-write solution for Xen and tested blktap2 with > the vhd backend. > > My Test: > > I''ve created a master-image with "dd" and installed WindowsXP on the image. > Then I used vhd-util to create a copy-on-write-image for the master-image. > > After booting the VM and logging in the, the cow-image had a size of 260 > MB. That''s a little bit weird, because I didn''t really changend any data.Just one word: swap. Christian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Am Donnerstag 24 Juni 2010 10:41:30 schrieben Sie:> Am Mittwoch, 23. Juni 2010, 17:26:05 schrieb Bastian de Groot: > > Hi everybody, > > > > I am searching for a copy-on-write solution for Xen and tested blktap2 > > with the vhd backend. > > > > My Test: > > > > I''ve created a master-image with "dd" and installed WindowsXP on the > > image. Then I used vhd-util to create a copy-on-write-image for the > > master-image. > > > > After booting the VM and logging in the, the cow-image had a size of 260 > > MB. That''s a little bit weird, because I didn''t really changend any data. > > Just one word: swap. > > ChristianGood guess! I''ve tested it with deactivated swap in WindowsXP, but it didn''t have any effect. The results were the same. Bastian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel