Ceph » rbd

root@client02:/usr/src/qemu-kvm# ./qemu-img create -f rbd rbd:rbd/alpha 10G
Formatting 'rbd:rbd/alpha', fmt=rbd size=10737418240 cluster_size=0 
10.07.29_23:05:47.284173 7f4b36ae8720 librados: starting msgr at :/0
10.07.29_23:05:47.284451 7f4b36ae8720 librados: starting objecter
10.07.29_23:05:47.284603 7f4b36ae8720 librados: setting wanted keys
10.07.29_23:05:47.284633 7f4b36ae8720 librados: iit
10.07.29_23:05:47.287827 7f4b36ae8720 librados: waiting for osdmap
10.07.29_23:05:47.289148 7f4b36ae8720 librados: init done
10.07.29_23:05:47.291103 7f4b36ae8720 librados: Objecter returned from stat
failed assigning block id
10.07.29_23:05:47.779491 7f4b36ae8720 librados: shutdown
qemu-img: rbd:rbd/alpha: error while creating rbd: Input/output error
root@client02:/usr/src/qemu-kvm#

root@node14:~# rbd --size 10240 create alpha
failed to assign a block name for image
create error: Operation not supported
root@node14:~#

Searching through qemu-kvm i found that it fails in "block/rbd.c" on line 202:

rados_exec(pool, info_oid, "rbd", "assign_bid", NULL, 0, (char *)out, sizeof(out));

There is a "rbd_info" object created in the "rbd" pool, but it is empty.