Hi, I'm facing an issue with starting 1 monitor. In the relevant error log the issue seems to be clear: root@ld5506:~# tail -n 30 /var/log/ceph/ceph-mon.ld5506.log 2019-10-28 17:14:46.471 7f157b097440  0 set uid:gid to 64045:64045 (ceph:ceph) 2019-10-28 17:14:46.471 7f157b097440  0 ceph version 14.2.4 (65249672c6e6d843510e7e01f8a4b976dcac3db1) nautilus (stable), process ceph-mon, pid 421378 2019-10-28 17:14:46.471 7f157b097440 -1 error: monitor data filesystem reached concerning levels of available storage space (available: 5% 11 GiB) you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%) 2019-10-28 17:14:56.563 7fb006b4c440  0 set uid:gid to 64045:64045 (ceph:ceph) 2019-10-28 17:14:56.563 7fb006b4c440  0 ceph version 14.2.4 (65249672c6e6d843510e7e01f8a4b976dcac3db1) nautilus (stable), process ceph-mon, pid 421600 2019-10-28 17:14:56.563 7fb006b4c440 -1 error: monitor data filesystem reached concerning levels of available storage space (available: 5% 11 GiB) you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%) 2019-10-28 17:15:06.823 7fb2c7084440  0 set uid:gid to 64045:64045 (ceph:ceph) 2019-10-28 17:15:06.823 7fb2c7084440  0 ceph version 14.2.4 (65249672c6e6d843510e7e01f8a4b976dcac3db1) nautilus (stable), process ceph-mon, pid 421824 2019-10-28 17:15:06.823 7fb2c7084440 -1 error: monitor data filesystem reached concerning levels of available storage space (available: 5% 11 GiB) you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%) 2019-10-28 17:15:17.067 7f722b0c4440  0 set uid:gid to 64045:64045 (ceph:ceph) 2019-10-28 17:15:17.067 7f722b0c4440  0 ceph version 14.2.4 (65249672c6e6d843510e7e01f8a4b976dcac3db1) nautilus (stable), process ceph-mon, pid 422009 2019-10-28 17:15:17.067 7f722b0c4440 -1 error: monitor data filesystem reached concerning levels of available storage space (available: 5% 11 GiB) you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%) 2019-10-28 17:15:27.323 7f34e37df440  0 set uid:gid to 64045:64045 (ceph:ceph) 2019-10-28 17:15:27.323 7f34e37df440  0 ceph version 14.2.4 (65249672c6e6d843510e7e01f8a4b976dcac3db1) nautilus (stable), process ceph-mon, pid 422197 2019-10-28 17:15:27.323 7f34e37df440 -1 error: monitor data filesystem reached concerning levels of available storage space (available: 5% 11 GiB) you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%) However there is now sufficient disk space available on this node after completing some file cleanup: root@ld5506:~# btrfs filesystem usage / Overall:     Device size:                 192.54GiB     Device allocated:            183.54GiB     Device unallocated:            9.00GiB     Device missing:                  0.00B     Used:                        110.76GiB     Free (estimated):             75.01GiB      (min: 70.51GiB)     Data ratio:                       1.00     Metadata ratio:                   2.00     Global reserve:              237.86MiB      (used: 0.00B) Data,single: Size:175.53GiB, Used:109.51GiB    /dev/sdbq3    175.53GiB Metadata,DUP: Size:4.00GiB, Used:639.77MiB    /dev/sdbq3      8.00GiB System,DUP: Size:8.00MiB, Used:48.00KiB    /dev/sdbq3     16.00MiB Unallocated:    /dev/sdbq3      9.00GiB I would expect that +70GB disk space must be sufficient for MON to start. Please advise how to fix this error. THX