On 10.10.2014 02:19, Marcus White wrote: > > For VMs, I am trying to visualize how the RBD device would be exposed. > Where does the driver live exactly? If its exposed via libvirt and > QEMU, does the kernel driver run in the host OS, and communicate with > a backend Ceph cluster? If yes, does libRBD provide a target (SCSI?) > interface which the kernel driver connects to? Trying to visualize > what the stack looks like, and the flow of IOs for block devices.
For VMs, the RBD is not exposed at all. The communication is made in userland space of the host kernel, qemu uses librados directly, no kernel driver involved. The VM guest kernel sees a virtual block device presented by qemu. Regards -- Robert Sander Heinlein Support GmbH Schwedter Str. 8/9b, 10119 Berlin http://www.heinlein-support.de Tel: 030 / 405051-43 Fax: 030 / 405051-19 Zwangsangaben lt. §35a GmbHG: HRB 93818 B / Amtsgericht Berlin-Charlottenburg, Geschäftsführer: Peer Heinlein -- Sitz: Berlin
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