Ceph: Status shows "Reduced data availability: xx pgs inactive, xx pgs peering"

Issue

Ceph status returns "[WRN] PG_AVAILABILITY: Reduced data availability: xx pgs inactive, xx pgs peering"

Example:

# ceph -s
  cluster:
    id:     5b3c2fd{Cluster ID Obfuscated}16bfb00
    health: HEALTH_WARN
            1 MDSs report slow metadata IOs
            1 MDSs report slow requests
            1 MDSs behind on trimming
            Reduced data availability: 6 pgs inactive, 6 pgs peering     <--- Here

  services:
    mon: 3 daemons, quorum e,f,h (age 22h)
    mgr: a(active, since 25h)
    mds: 1/1 daemons up, 1 hot standby
    osd: 6 osds: 6 up (since 3h), 6 in (since 3h); 60 remapped pgs

  data:
    volumes: 1/1 healthy
    pools:   4 pools, 193 pgs
    objects: 378.73k objects, 98 GiB
    usage:   315 GiB used, 2.6 TiB / 2.9 TiB avail
    pgs:     3.109% pgs not active
             243503/1136184 objects misplaced (21.432%)
             127 active+clean
             59  active+remapped+backfill_wait
             6   peering                                                <--- Here
             1   active+remapped+backfilling

  io:
    client:   102 B/s wr, 0 op/s rd, 0 op/s wr
    recovery: 1.7 MiB/s, 8 objects/s

From Ceph Health Detail

# ceph health detail:
HEALTH_WARN 1 MDSs report slow metadata IOs; 1 MDSs report slow requests; 1 MDSs behind on trimming; Reduced data availability: 6 pgs inactive, 6 pgs peering
[WRN] MDS_SLOW_METADATA_IO: 1 MDSs report slow metadata IOs
    mds.ocs-storagecluster-cephfilesystem-b(mds.0): 100+ slow metadata IOs are blocked > 30 secs, oldest blocked for 13158 secs
[WRN] MDS_SLOW_REQUEST: 1 MDSs report slow requests
    mds.ocs-storagecluster-cephfilesystem-b(mds.0): 84356 slow requests are blocked > 30 secs
[WRN] MDS_TRIM: 1 MDSs behind on trimming
    mds.ocs-storagecluster-cephfilesystem-b(mds.0): Behind on trimming (261/128) max_segments: 128, num_segments: 261
[WRN] PG_AVAILABILITY: Reduced data availability: 6 pgs inactive, 6 pgs peering   \
    pg 1.25 is stuck peering for 86m, current state peering, last acting [2,3,1]   \
    pg 1.43 is stuck peering for 74m, current state peering, last acting [2,1,3]    \
    pg 1.44 is stuck peering for 86m, current state peering, last acting [2,3,5]     Here
    pg 1.63 is stuck peering for 97m, current state peering, last acting [2,5,3]    /
    pg 3.4 is stuck peering for 74m, current state peering, last acting [2,5,3]    /
    pg 3.1f is stuck peering for 86m, current state peering, last acting [2,5,0]  /