Hi, On Thu, Oct 13, 2011 at 5:54 PM, Fabian Wenk <[email protected]> wrote:
I hope this helps and my information are correct, if not, could somebody > from OpenNebula please correct me. > Thank you for your great contributions to the list! I'd like to add that we tried to summarize the implications of the shared [1] and non-shared [2] approaches in the documentation, let us know if there are any big gaps we forgot about. Regards. [1] http://opennebula.org/documentation:rel3.0:sfs#considerations_limitations [2] http://opennebula.org/documentation:rel3.0:nsfs#considerations_limitations -- Carlos Martín, MSc Project Engineer OpenNebula - The Open Source Toolkit for Cloud Computing www.OpenNebula.org <http://www.opennebula.org/> | [email protected] On Thu, Oct 13, 2011 at 5:54 PM, Fabian Wenk <[email protected]> wrote: > Hello Humberto > > > On 13.10.2011 11:03, Humberto N. Castejon Martinez wrote: > >> Reading the Opennebula documentation, I believe there are two things I >> have >> to deal with: >> >> 1) The image repository, and whether it is shared or not between the >> front-end and the workers >> > > I have some persistent Images which are used for "persistent" VMs. I have > the images folder shared with NFS and I use tm_nfs. When starting a VM with > a persistent images, it creates only a soft link in VM_DIR which points to > the image in the images folder. If you want to have copied the persistent > image into the VM_DIR on the cluster node, you would need tm_ssh. But then > on startup the whole image will be copied to the cluster node into VM_DIR > and on shutdown it will be copied back to the images folder. > > > 2) The<VM_DIR>, that contains deployment files, etc for the VMs running on >> a worker. This directory may or not be shared between the front-end and >> the >> workers, but it should always be shared between the workers if we want >> live >> migration, right? >> > > If you use tm_ssh you do not need to share this, if you use tm_nfs, you > need to have it shared. The same with the images folder. For live migration > you need a shared images folder and VM_DIR. > > > Some of the questions I have are these (sorry if some of them seem stupid >> :-)): >> > > They are not stupid, It took me some time to try out and see through how > this things works, and so I had to change my setup a few times until > OpenNebula an I were happy. > > > - What are the implications of sharing or not the image repository >> between >> the front-end and the workers (apart from the need to transfer images to >> the >> worker nodes in the latter case)? >> > > See above. > > > - What are the implications of sharing or not the<VM_DIR> between the >> front-end and the workers? >> > > Also above. > > > - Can I use ZFS or MooseFs and still be able to live migrate VMs? >> > > MooseFS [1] is a fault tolerant, network distributed file system (eg. over > several servers). I do not know if ZFS can do this. MooseFS is similar like > NFS, only that the data are distributed over several servers (including your > local server). I guess live migration should work. > > [1] http://www.moosefs.org/ > > > - Will the<VM_DIR> always hold a (copy of a) VM image for every VM >> running >> on a worker? Must the<VM-DIR> be in the local hard drive of a worker or >> may >> it reside on an external shared storage? >> > > See above, if used with tm_nfs, it is on a external shared storage (NFS > server). When used with tm_ssh, it is on the local disk and all images > (public or persistent) will be copied in full through ssh. > > > I guess two factors i should also consider when choosing a solution are >> the >> following, right? >> >> - The speed of transferring VM images >> - The speed of cloning VM images >> > > Yes. Access to a persistent image through NFS only transfers the data > needed, cloning always creates a full copy. When you use tm_ssh, the image > will always be copied in full through ssh (which also gives some CPU > overhead on the front end and cluster node). > > I hope this helps and my information are correct, if not, could somebody > from OpenNebula please correct me. > > > bye > Fabian > ______________________________**_________________ > Users mailing list > [email protected] > http://lists.opennebula.org/**listinfo.cgi/users-opennebula.**org<http://lists.opennebula.org/listinfo.cgi/users-opennebula.org> >
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