3 crush_tunables: firefly
5 - must scrub before tier agent can activate
9 - sudo ceph osd pool create base 4
10 - sudo ceph osd pool create cache 4
11 - sudo ceph osd tier add base cache
12 - sudo ceph osd tier cache-mode cache writeback
13 - sudo ceph osd tier set-overlay base cache
14 - sudo ceph osd pool set cache hit_set_type bloom
15 - sudo ceph osd pool set cache hit_set_count 8
16 - sudo ceph osd pool set cache hit_set_period 60
17 - sudo ceph osd pool set cache target_max_objects 250
18 - sudo ceph osd pool set cache min_read_recency_for_promote 2
19 - sudo ceph osd pool set cache min_write_recency_for_promote 2