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restdeploymentceph

Ceph status HEALTH_WARN while adding an RGW Instance


I want to create ceph cluster and then connect to it through S3 RESTful api. So, I've deployed ceph cluster (mimic 13.2.4) on "Ubuntu 16.04.5 LTS" with 3 OSD (one per each HDD 10Gb).

Using this tutorials:

1) http://docs.ceph.com/docs/mimic/start/quick-start-preflight/#ceph-deploy-setup

2) http://docs.ceph.com/docs/mimic/start/quick-ceph-deploy/ At this point, ceph status is OK:

root@ubuntu-srv:/home/slavik/my-cluster# ceph -s
  cluster:
    id:     d7459118-8c16-451d-9774-d09f7a926d0e
    health: HEALTH_OK



  services:
    mon: 1 daemons, quorum ubuntu-srv
    mgr: ubuntu-srv(active)
    osd: 3 osds: 3 up, 3 in

  data:
    pools:   0 pools, 0 pgs
    objects: 0  objects, 0 B
    usage:   3.0 GiB used, 27 GiB / 30 GiB avail
    pgs:

3) "To use the Ceph Object Gateway component of Ceph, you must deploy an instance of RGW. Execute the following to create an new instance of RGW:"

root@ubuntu-srv:/home/slavik/my-cluster# ceph-deploy rgw create ubuntu-srv
....
[ceph_deploy.rgw][INFO  ] The Ceph Object Gateway (RGW) is now running on host ubuntu-srv and default port 7480
root@ubuntu-srv:/home/slavik/my-cluster# ceph -s
  cluster:
    id:     d7459118-8c16-451d-9774-d09f7a926d0e
    health: HEALTH_WARN
            too few PGs per OSD (2 < min 30)

  services:
    mon: 1 daemons, quorum ubuntu-srv
    mgr: ubuntu-srv(active)
    osd: 3 osds: 3 up, 3 in

  data:
    pools:   1 pools, 8 pgs
    objects: 0  objects, 0 B
    usage:   3.0 GiB used, 27 GiB / 30 GiB avail
    pgs:     37.500% pgs unknown
             62.500% pgs not active
             5 creating+peering
             3 unknown

Ceph status has been changed to HEALTH_WARN - why and how to resolve it?


Solution

  • Your issue is

    health: HEALTH_WARN
            too few PGs per OSD (2 < min 30)
    

    Look at you current pg config by running:

    ceph osd dump|grep pool

    See what each pool is configured for pg count, then goto https://ceph.com/pgcalc/ to calculate what your pools should be configured for.

    The warning is that you have a low number of pg's per osd, right now you have 2 per osd, where min should be 30