systemd: Increase max files open limit for OSD daemon
Owen Synge writes in https://github.com/ceph/ceph/commit/ebda4ba1c67172852587e47a8e6fb538809a1b1c
Under heavy load the number of file descriptors opened
by the OSD can go beyond the 64K file limit. This patch
increases the default to 128K.
Fixed in master by https://github.com/ceph/ceph/pull/4417