Before importing data to a cluster, carefully consider your service needs and plan the cluster's data structure and distribution in advance. This includes properly designing indexes and deciding on the appropriate number of index shards. To ensure optimal performance and scalability for a cluster, consider following these best practices:
- The size of a single shard: Keep the size of each shard between 10 GB and 50 GB. This helps strike a balance between storage efficiency and query performance.
- Memory-to-shards ratio: Limit the number of shards per 1 GB of memory to 20 to 30. This ensures that each shard has sufficient memory resources to respond to indexing and query requests.
- Number of shards per node: To prevent node overload, keep the number of shards on each node under 1000. This helps to improve node stability.
- Relationship between the number of index shards and the number of nodes: For each index, make sure the number of shards is an integral multiple of the total number of data nodes and cold data nodes in the cluster. This helps improve load balancing and optimize query and indexing performance.
- Total number of shards in a cluster: To facilitate management and avoid oversized shards, make sure the total number of shards in a cluster is less than 30,000. This helps maintain the stability and responsiveness of the cluster.
Following these suggestions, you can plan and manage index shards for a CSS cluster more effectively, improving the cluster's overall performance and maintainability.