RBD Tracing with Jaeger

Hello everyone, To understand the flow of rgw I used the ceph cluster by this "RGW=1 ../src/vstart.sh -d -n -x" and then "ps ax|grep rgw" command will give me the pid of rgw server, and then I used to do "gdb -p ${pid}" obtained from above. Now I want to understand RBD work flow but when I do "ps ax|grep rbd" then it is not showing any process related to "rbd" , I even tried it with "RBD=1 ../src/vstart.sh -d -n -x" but it did not work. Can anyone tell how to find pid process of rbd server?, or so that I can attach gdb to it. Thank You.