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How to Check Ceph's Status and Disk Usage

Introduction​

Ceph was selected as the storage solution for Private Cloud Core OpenStack clouds due to its ability store data in a replicated fashion. The data stored in the Ceph cluster is accessible from any of your cloud's control plane nodes. The storage is considered shared across all nodes, which can make recovering an instance and its data trivial. As an administrator of this cloud, we aim to provide you information about how you can check the status of your Ceph cluster and see available disk usage using the command line.

Prerequisites​

  • Root access to your cloud's control plane nodes

Check Ceph Status​

To check the status of your Ceph cluster, use ceph status.

For example:

# ceph status
  cluster:
    id:     34fa49b3-fff8-4702-8b17-4e8d873c845f
    health: HEALTH_OK

  services:
    mon: 3 daemons, quorum relaxed-flamingo,focused-capybara,lovely-ladybug (age 2w)
    mgr: relaxed-flamingo(active, since 2w), standbys: focused-capybara, lovely-ladybug
    osd: 4 osds: 4 up (since 3d), 4 in (since 3d)
    rgw: 3 daemons active (focused-capybara.rgw0, lovely-ladybug.rgw0, relaxed-flamingo.rgw0)

  task status:

  data:
    pools:   13 pools, 337 pgs
    objects: 69.28k objects, 250 GiB
    usage:   724 GiB used, 11 TiB / 12 TiB avail
    pgs:     337 active+clean

  io:
    client:   121 KiB/s rd, 1.2 MiB/s wr, 137 op/s rd, 232 op/s wr

Check Ceph Disk Usage​

To check the available disk space in your Ceph cluster, use ceph df.

For example:

# ceph df
--- RAW STORAGE ---
CLASS  SIZE    AVAIL   USED     RAW USED  %RAW USED
ssd    12 TiB  11 TiB  720 GiB   724 GiB       6.08
TOTAL  12 TiB  11 TiB  720 GiB   724 GiB       6.08

--- POOLS ---
POOL                       ID  PGS  STORED   OBJECTS  USED     %USED  MAX AVAIL
device_health_metrics       1    1  286 KiB        4  858 KiB      0    3.4 TiB
images                      2   32  7.6 GiB    1.02k   23 GiB   0.22    3.4 TiB
volumes                     3   32   88 GiB   23.61k  264 GiB   2.45    3.4 TiB
vms                         4   32  144 GiB   39.92k  433 GiB   3.96    3.4 TiB
backups                     5   32      0 B        0      0 B      0    3.4 TiB
metrics                     6   32   25 MiB    4.49k  127 MiB      0    3.4 TiB
manila_data                 7   32      0 B        0      0 B      0    3.4 TiB
manila_metadata             8   32      0 B        0      0 B      0    3.4 TiB
.rgw.root                   9   32  3.6 KiB        8   96 KiB      0    3.4 TiB
default.rgw.log            10   32  3.4 KiB      207  384 KiB      0    3.4 TiB
default.rgw.control        11   32      0 B        8      0 B      0    3.4 TiB
default.rgw.meta           12    8    954 B        4   36 KiB      0    3.4 TiB
default.rgw.buckets.index  13    8  2.2 MiB       11  6.6 MiB      0    3.4 TiB