Zones for a sharded collection can be created either before or after the collection exists. At the same time, zones can be defined either on the shard key, or a prefix of it.

However, of those combinations, creating zones on a prefix of the shard key, and before the collection is created, currently fails with an InvalidOptions error, as shardCollection expects the zones to exactly match the shard key:

> db.adminCommand({updateZoneKeyRange: "test.xyzzy", min: {a:1}, max:{a:10}, zone:"BCN"})
> db.adminCommand({shardCollection: "test.xyzzy", key: {a:1, b:1}})
MongoServerError[InvalidOptions]: the proposed shard key { a: 1, b: 1 } does not match with the shard key of the existing zone { a: 1 } -->> { a: 10 }

Inverting the order of the operations works, however, this misses the benefits of the initial chunks being created so that data is distributed according to the zones without balancing:

> db.adminCommand({shardCollection: "test.foo", key: {a:1, b:1}})
> db.adminCommand({updateZoneKeyRange: "test.foo", min: {a:1}, max:{a:10}, zone:"BCN"})
{ ok: 1, [...] }

We should fix this limitation to avoid usability surprises for users.