What cinder volume is missing an RBD object ?

Although it is extremely unlikely to loose an object stored in Ceph, it is not impossible. When it happens to a Cinder volume based on RBD, knowing which has an object missing will help with disaster recovery.

The list_missing command shows rbd_data.9ad9d26b8b4567.00000000000007b1 is the name of the missing object.

# ceph pg 4.46 list_missing
{ "offset": { "oid": "",
      "key": "",
      "snapid": 0,
      "hash": 0,
      "max": 0,
      "pool": -1,
      "namespace": ""},
  "num_missing": 1,
  "num_unfound": 1,
  "objects": [
        { "oid": { "oid": "rbd_data.9ad9d26b8b4567.00000000000007b1",
              "key": "",
              "snapid": -2,
              "hash": 197180870,
              "max": 0,
              "pool": 4,
              "namespace": ""},
          "need": "328685'1233912",
          "have": "328683'1233904",
          "locations": []}],
  "more": 0}

The corresponding RBD image name is displayed by rbd info

# rbd --pool ovh ls |
   while read image ; do
      rbd --pool ovh info $image
    done | grep -C 5 9ad9d26b8b4567

        format: 2
        features: layering
rbd image 'volume-1f0c5446-8671-4096-9954-ed2cb8b1e33e':
        size 30720 MB in 7680 objects
        order 22 (4096 KB objects)
        block_name_prefix: rbd_data.9ad9d26b8b4567
        format: 2
        features: layering
rbd image 'volume-215afc73-21f0-4234-8389-f36bbe473300':
        size 10240 MB in 2560 objects
        order 22 (4096 KB objects)

The human readable name of the cinder volume is the last part of the RBD image and cinder show will display it:

# cinder show 1f0c5446-8671-4096-9954-ed2cb8b1e33e
...
|          display_name          |   osrm |
...
This entry was posted in Havana, ceph, openstack. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>