On 12/05/2009 11:29 PM, Daniel Schwager wrote: > Hi Morita (is this your first name ?), My first name is Kazutaka. In Japan, the first name follows the family name. Please call me Kazutaka. :) >>> 1. is it possible to use sheepdog as storage for resuming/suspending >>> KVM machines ? Normaly, kvm invokes a command like dd or cat to >>> store/restore the RAM to/from disk ... this may will not work >>> with sheepdog in the current version, or ? >> Not supported yet, but it will be supported in future. >> To support resuming/suspending, sheepdog need to support online >> snapshot. It is included in our TODO list. > > So, i currently cannot take a "normal"-KVM snapshot to a normal > filesystem (e.g. ext3) > using the normale KVM-snapshot approach ? Or do you mean, it's not > possible > to store these snapshots directly on the sheepdog-servers. > > May it's (later) possible to > 1) create a sheepdog volume manually > 2) start kvm-tools manually to store the suspend-data using to the > volume ? > Ok ... there's no sheepdog standalone-client to store data to the > volume. > KVM uses dd/cat to store data - but these commands cannot be used to > access your volume... > 3) resume the vm using kvm-tools manually (some problem - no standalone > sheepdog client) > 4) delete the sheepdog-volume manually Sorry, I was talking about qemu loadvm/savevm based suspend, and I don't know well about dd/cat based suspend. If stand-alone sheepdog client exists, kvm-tools may be able to suspend sheepdog vm with your approach, I guess. Creating such a client is not difficult if performance is not cared about. >>> 2. to be sure - the KVM machines could run on a sheepdog server > member, >>> but can also run on not-sheepdog-server machine connecting >>> to the sheepdog cluster via IP and multicast. >> It may be possible to support vm runs outside sheepdog servers. >> We currently assume virtual machines run on sheepdog server machines >> to enable zero-hop data accessing and to check vm is alive. >> We can think of removing this restriction if it is needed. > > In "big" (e.g. >10 KVM server) environment, the KVM-server boots > via PXE+diskless-NFS (we do ..) and has no or only a > small local HDD (using e.g. redhat satellite-server). This will > reduce overhead of keeping the servers in sync. > > Therefore, it make no sense to add big local storage to the systems. > It would be great, if you can add this issue > "kvm-server must not be a sheepdog-storage server" to your TODO-list (-: Okay, I think your environment is general and adding it to TODO items is meaningful. I'll add it. Thanks, MORITA Kazutaka |