In the Elasticsearch ecosystem, it's important to monitor nodes and clusters in order to manage and improve their performance and state. There are several issues that can arise at the cluster level, such as the following:
- Node overheads: Some nodes can have too many shards allocated and become a bottleneck for the entire cluster.
- Node shutdown: This can happen due to a number of reasons, for example, full disks, hardware failures, and power problems.
- Shard relocation problems or corruptions: Some shards can't get an online status.
- Shards that are too large: If a shard is too big, then the index performance decreases due to the merging of massive Lucene segments.
- Empty indices and shards: These waste memory and resources; however, because each shard has a lot of active threads, if there are a large number of unused indices and shards, then...
