[Top posting] I am planning to write a short blog to answer few similar questions that I received after posting this blog. Is iSCSI stack obligatory for block store ? Answer is No. It basically depends on the use case and choice. If we can run/manage target emulation on the client side, we don't have to bring iSCSI stack into picture. We simply export LUN using a loopback device i.e after creating the back end with qemu-tcmu storage module, we can directly export the target via loopback instead of iSCSI. So In this case we don't see overheads with iSCSI layers, but IMO overhead with iSCSI can be very minimal, may be I need the performance numbers to prove (will spin a benchmark soon) I have done some basic benchmarking taking baseline as Fuse mount and target as iSCSI exposed target via tcmu-runner, you can find them at [1] You can find more bechmark's at [2], the commit messages should explain you the configurations. Hope that answers most of your questions :) [1] https://htmlpreview.github.io/?https://github.com/pkalever/iozone_results_gluster/blob/master/block-store/iscsi-fuse-1/html_out/index.html [2] https://github.com/pkalever/iozone_results_gluster/blob/master/block-store/ -- Prasanna On Mon, Nov 7, 2016 at 2:23 PM, Gandalf Corvotempesta <gandalf.corvotempesta@xxxxxxxxx> wrote: > Il 07 nov 2016 09:23, "Lindsay Mathieson" <lindsay.mathieson@xxxxxxxxx> ha > scritto: >> >> From a quick scan, there doesn't seem to be any particular advantage >> over qemu using gfapi directly? Is this more aimed at apps that can't >> use gfapi such as vmware or as a replacement for NFS? >> > > Dump question: why should i use a block storage replacing nfs? > Nfs-ganesha makes use of libgfapi, block storage does the same but also need > the whole iscsi stack so performance could be lower > > If i don't need direct access to a block device on the client (in example > for creating custom FS or LVM and so on), the nfs ganesha should be a better > approach, right? > > Anyone compared performances between: > > 1. Fuse mount > 2. Nfs > 3. Nfs ganesha > 4. Qemu direct access via gfapi > 5. Iscsi > > ? _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://www.gluster.org/mailman/listinfo/gluster-users
