Besides running on one server there are also some other concerns with this deployment.
- Using the date field (which is monotomically increaseing) is not the best for a shard key. See here. This can lead to a “hot” shard because the data isn’t actually balanced as time goes on, the older date range will not be used as much as time moves forward. This can cause a small amount of the shards to handle most of the queries thus making your sharding kind of useless.
- You have 11 different shards but does your query use the shard key as a prefix? If not you will get scatter gather queries across all 11 shards. Instead of direct and specific queries going to the correct shard only.
- Standalone shards are not recommended because if one of the nodes goes down that portion of the data isn’t available since it’s distributed across the shards.
- Finally Sharding isn’t a “magic” solution that give instant performance as said before your queries have to be optimized so they are routed by the mongos correctly.