What Are the Impacts If an Elasticsearch Cluster of CSS Has Too Many Shards?

A large number of shards in a cluster slows down shard creation.
If automatic index creation is enabled, slow index creation may cause a large number of write requests to be stacked in the memory or result in a cluster breakdown.
If there are too many shards and you cannot properly monitor workloads, the number of records in a single shard may exceed the threshold, and write requests may be denied.

Parent topic: Using CSS Cluster Search Engines