Why does Red Hat Ceph Storage reports a high USED space after a fresh installation?

Issue

• After a fresh Ceph installation, the usage field in the output of ceph -s is showing 12 TiB:

  [root@node01 ~]# ceph -s
    cluster:
      id:     <cluster-id>
      health: HEALTH_OK
    services:
      mon: 3 daemons, quorum node02,node03,node01 (age 2h)
      mgr: node02.qkbcsi(active, since 2h), standbys: node03.svhevu, node01.dlmmxp
      osd: 96 osds: 96 up (since 88m), 96 in (since 89m)
    data:
      pools:   1 pools, 1 pgs
      objects: 0 objects, 0 B
      usage:   12 TiB used, 1.4 PiB / 1.4 PiB avail
      pgs:     1 active+clean
  

• Outputs of ceph df and rados df:

  [root@node01 ~]# ceph df
  --- RAW STORAGE ---
  CLASS     SIZE    AVAIL    USED  RAW USED  %RAW USED
  hdd    1.4 PiB  1.4 PiB  12 TiB    12 TiB       0.83
  TOTAL  1.4 PiB  1.4 PiB  12 TiB    12 TiB       0.83
  --- POOLS ---
  POOL                   ID  PGS  STORED  OBJECTS  USED  %USED  MAX AVAIL
  device_health_metrics   1    1     0 B        0   0 B      0    442 TiB
  
  [root@node01 ~]# rados df
  POOL_NAME              USED  OBJECTS  CLONES  COPIES  MISSING_ON_PRIMARY  UNFOUND  DEGRADED  RD_OPS   RD  WR_OPS   WR  USED COMPR  UNDER COMPR
  device_health_metrics   0 B        0       0       0                   0        0         0       0  0 B       0  0 B         0 B          0 B
  total_objects    0
  total_used       12 TiB
  total_avail      1.4 PiB
  total_space      1.4 PiB
  

• Why is this occurring?

• Where is this high amount of USEDspace coming from?