Re: [Qemu-devel] Live migration using qcow2

2013-02-21 Thread Dietmar Maurer
> On Thu, Feb 21, 2013 at 12:02:18PM +, Dietmar Maurer wrote: > > > The problem is about cache coherency. Local files work just fine > > > with cache=writeback, but if you migrate to a different host, you > > > get the problem that the destination kernel may cache some parts of > > > the image

Re: [Qemu-devel] Live migration using qcow2

2013-02-21 Thread Kevin Wolf
On Thu, Feb 21, 2013 at 12:02:18PM +, Dietmar Maurer wrote: > > The problem is about cache coherency. Local files work just fine with > > cache=writeback, but if you migrate to a different host, you get the problem > > that the destination kernel may cache some parts of the image while the > >

Re: [Qemu-devel] Live migration using qcow2

2013-02-21 Thread Dietmar Maurer
> The problem is about cache coherency. Local files work just fine with > cache=writeback, but if you migrate to a different host, you get the problem > that the destination kernel may cache some parts of the image while the source > is still writing to it. When you do the actual switch to the dest

Re: [Qemu-devel] Live migration using qcow2

2013-02-20 Thread Tiziano Müller
Am Mittwoch, den 20.02.2013, 15:16 +0100 schrieb Paolo Bonzini: > Il 20/02/2013 14:46, Kevin Wolf ha scritto: > >> > Thanks for the fast reply. Can you please elaborate on that (or post a > >> > link to an explanation): What exactly does the backend have to provide > >> > that for example cache=wri

Re: [Qemu-devel] Live migration using qcow2

2013-02-20 Thread Paolo Bonzini
Il 20/02/2013 14:46, Kevin Wolf ha scritto: >> > Thanks for the fast reply. Can you please elaborate on that (or post a >> > link to an explanation): What exactly does the backend have to provide >> > that for example cache=writeback can be used? Is there a way to test for >> > it? > The problem is

Re: [Qemu-devel] Live migration using qcow2

2013-02-20 Thread Kevin Wolf
On Wed, Feb 20, 2013 at 02:14:47PM +0100, Tiziano Müller wrote: > Am Mittwoch, den 20.02.2013, 12:20 +0100 schrieb Kevin Wolf: > > On Wed, Feb 20, 2013 at 11:47:56AM +0100, Tiziano Müller wrote: > > > Hi everyone > > > > > > According to http://wiki.qemu.org/Migration/Storage section "Image > > >

Re: [Qemu-devel] Live migration using qcow2

2013-02-20 Thread Tiziano Müller
Am Mittwoch, den 20.02.2013, 12:20 +0100 schrieb Kevin Wolf: > On Wed, Feb 20, 2013 at 11:47:56AM +0100, Tiziano Müller wrote: > > Hi everyone > > > > According to http://wiki.qemu.org/Migration/Storage section "Image > > Formats" qemu can't do live migration without data corruption when using > >

Re: [Qemu-devel] Live migration using qcow2

2013-02-20 Thread Kevin Wolf
On Wed, Feb 20, 2013 at 11:47:56AM +0100, Tiziano Müller wrote: > Hi everyone > > According to http://wiki.qemu.org/Migration/Storage section "Image > Formats" qemu can't do live migration without data corruption when using > qcow2 or qed due to the metadata caches. > Wasn't that fixed by commit 0

[Qemu-devel] Live migration using qcow2

2013-02-20 Thread Tiziano Müller
Hi everyone According to http://wiki.qemu.org/Migration/Storage section "Image Formats" qemu can't do live migration without data corruption when using qcow2 or qed due to the metadata caches. Wasn't that fixed by commit 06d9260 ? Also, "Clustered File Systems" does not seem to be up-to-date sinc