I am little bit confuse in shard and collection. We can make a index a new table to new shard and can be done same as a collection.
When to make a new shard and When make a new collection.
A collection is a complete logical index in a SolrCloud cluster. e.g you might have three different collections called users,books,people.
On a Logical level the whole index is called a collection. which might be spread over many nodes in the cluster.
A shard is a slice of that whole collection. i.e a collection is made of one or more shards.
When to use collection ?
Generally, users will create multiple Collections to separate logical units of data that will not be intermingled, similar to a database in the relational world. Collections are generally isolated from one another and do not typically communicate with each other. Also each Collections will each have their own unique schema.xml to define the types for their index.
When to use a shard?
If you feel your index is too big to be stored on one node . it can be divided into different shards and can be stored on different nodes on a cluster.
Read more about it here : https://thinkbiganalytics.com/solrcloud-terminology/