> From: Kevin Wolf [mailto:kw...@redhat.com] > Am 28.09.2016 um 11:32 hat Pavel Dovgalyuk geschrieben: > > > From: Kevin Wolf [mailto:kw...@redhat.com] > > > Am 27.09.2016 um 16:06 hat Pavel Dovgalyuk geschrieben: > > > > > From: Kevin Wolf [mailto:kw...@redhat.com] > > > > > Am 26.09.2016 um 11:51 hat Pavel Dovgalyuk geschrieben: > > > > > > > From: Kevin Wolf [mailto:kw...@redhat.com] > > > > > > > Am 26.09.2016 um 10:08 hat Pavel Dovgalyuk geschrieben: > > > > > Originally, we only called bdrv_goto_snapshot() for all _top level_ > > > > > BDSes, and this is still what you normally get. However, if you > > > > > explicitly create a BDS (e.g. with its own -drive option), it is > > > > > considered a top level BDS without actually being top level for the > > > > > guest, and therefore the snapshotting function is called for it. > > > > > > > > > > Of course, this is highly inefficient because the goto_snapshot > > > > > request > > > > > is passed by the filter driver and then called another time for the > > > > > lower node, effectively loading the snapshot a second time. > > > > Maybe double-saving/loading does the smallest damage then? > > And we should just document how to use blkreplay effectively? > > > > > > > > > > > > On the other hand if you use a single -drive option to create both the > > > > > qcow2 BDS and the blkreplay filter, we do need to pass down the > > > > > goto_snapshot request because it won't be called for the qcow2 layer > > > > > otherwise. > > > > > > > > How this can be specified in command line? > > > > I believed that separate -drive option is required. > > > > > > Something like this: > > > > > > -drive driver=blkreplay,image.driver=file,image.filename=test.img > > > > > > > I tried the following command line, but VM does not detect the hard drive > > and cannot boot. > > > > -drive > > driver=blkreplay,if=none,image.driver=file,image.filename=testdisk.qcow,id=img- > blkreplay > > -device ide-hd,drive=img-blkreplay > > My command line was assuming a raw image. It looks like you're using a > qcow (hopefully qcow2?) image. If so, then you need to include the qcow2 > driver: > > -drive driver=blkreplay,if=none,image.driver=qcow2,\ > image.file.driver=file,image.file.filename=testdisk.qcow,id=img-blkreplay
This doesn't work for some reason. Replay just hangs at some moment. Maybe there exists some internal difference between command line with one or two -drive options? Pavel Dovgalyuk
