Hi, experts, we are using cephfs with 16.2.* with multi active mds, and recently we see a strange thing, we have some c++ code about read file from cephfs. the client code just call very base read(), and when the cluster hit mds has slow request, and later the cluster back to normal. the read hang. then we need to gdb attach -p `pid of c++ process`, just attach, do nothing, the code then continue running. Our question is why this happens? and config could tune or we need change out c++ read code? Thanks xz