Comment 8 for bug 1263691

Jay, I think the situation for Glance is somewhat different from Cinder. For Glance, the glance-api service acts like a relay point for backing store, since the uploaded images has to be transferred to glance-api and then be stored on back-end. For large images, this process could take quite a while (couple of seconds to even minutes), so the 'queued' state for images indicates the glance service have received uploaded image and is working on putting it to backing store, which is a end user visible normal procedure.
On the contrary, what happens after user submits 'create' request and before the volume is available usually takes only a few jitters to finish because it's just a few message delivery between cinder services and a quick decision making process. End users usually barely notice the 'creating' state of volume until things go wrong. But request left in message queue not being picked up is only one of the failure cases, other bad things can happen and cause the similar 'symptom' - stuck at 'creating' state too, for example, message lost/low delivery due to network congestion. So I think 'queued' state is not suitable for Cinder in general.