Shard a collection

Command

sh.shardCollection("shop.customer", { customerId: "hashed" })

What it does

Shards the specified collection on the given shard key.

When to use it

When you want to distribute a growing collection across multiple shards.

Caution

The shard key can be changed with reshardCollection in 5.0+ (and extended with refineCollectionShardKey in 4.4+), but this is expensive because it redistributes all of the data; a poor key choice leads to uneven distribution.