Assessment
Before changing shards, you need to carry out a preliminary evaluation and determine the number of new shards, whether to scale up the current DDM node class, and the number of required data nodes and their specifications.
- Data volume: Run show db status to query the volume of data involved.
- DDM node class: Determine nodes of the DDM instance and vCPUs and memory size of each node.
- Data node class: Determine the number of data nodes and vCPUs and memory size of each node.
- Business scale: Analyze current service scale and growth trend. Changing shards is a critical operation for data change. You are advised to postpone this operation if the storage space of a data node is sufficient.
- Whether to add shards: Adding shards leads to sharding rule changes. All data in the current schema needs to be rebalanced based on the new sharding rule. This process is slow and requires more resources.
- Whether to perform DDL operations during shard change: Read and write services are not affected. To ensure data consistency, do not perform DDL operations during shard change.
Parent topic: Shard Configuration