Le vendredi 20 juin 2008 à 09:07 -0500, Javier Guerra a écrit : > On Fri, Jun 20, 2008 at 7:23 AM, carlopmart <[EMAIL PROTECTED]> wrote: > > Felix Leimbach wrote: > >> > >>> This is my first post to this list. I have already installed kvm-70 > >>> under rhel5.2. My intention is to share on disk image betwwen two rhel5.2 > >>> kvm guests. Is it possible to accomplish this in kvm like xen or vmware > >>> does?? How can I do?? I didn't find any reference abou this on kvm > >>> documentation ... > > i tried this looong ago and didn't really work because there was some > userspace cache on each QEMU instance. but the -drive option has a > 'cache=off' setting that should be enough. > > in theory (i haven't tested, but Avi 'blessed' it): > - create a new image with qemu-img > - add it to the command line using -drive file=xxx,cache=off on both > KVM instances > - use a cluster filesystem!
RFC: Well, well, perhaps it is delusions of a sick mind but since the introduction of qemu-nbd I think we can develop easily something to share a disk between several virtual hosts: I- in a first step, we can modify qemu-nbd to accept several connections for one disk image, for instance: # qemu-nbd my-disk.qcow2 # nbd-client localhost 1024 /dev/nbd0 # nbd-client localhost 1024 /dev/nbd1 and start two virtual hosts: "qemu -hda v1.img -hdb /dev/nbd0" and "qemu -hda v2.img -hdb /dev/nbd1" Of course the filesystem must know how to share the access to the disk with others (-> "cluster filesystem") II- in a second step, we can include directly the nbd protocol in qemu (block-nbd.c, "-drive file=nbd:localhost:1024") to connect to the server. We can also add some commands to the protocol to manage lock, HA, "what else ?" (Hi George). Any comments ? Cheers, Laurent -- ------------- [EMAIL PROTECTED] -------------- "In short: just say NO TO DRUGS and maybe you won't end up like the Hurd people." -- Linus Torvald -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
