Choose Y or M here to include cephlib, which provides the common functionality to both the Ceph filesystem and to the rados block device (rbd). More information at http://ceph.newdream.net/. If unsure, say N.
If you say Y here, debug output will include a filename and line to aid debugging. This increases kernel size and slows execution slightly when debug call sites are enabled (e.g., via CONFIG_DYNAMIC_DEBUG). If unsure, say N.