Increase max files open limit for OSD daemon.

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.

Signed-off-by: Owen Synge <osynge@suse.com>
(cherry picked from commit ebda4ba)

systemd/ceph-osd@.service

@@ -9,6 +9,7 @@ EnvironmentFile=-/etc/sysconfig/ceph
 Environment=CLUSTER=ceph
 ExecStart=/usr/bin/ceph-osd -f --cluster ${CLUSTER} --id %i
 ExecStartPre=/usr/libexec/ceph/ceph-osd-prestart.sh --cluster ${CLUSTER} --id %i
+LimitNOFILE=131072
 
 [Install]
 WantedBy=ceph.target