What is the consequence of running a four-node RF2 cluster at 81% storage utilization?

When a four-node cluster is configured with a replication factor of 2 (RF2), it requires sufficient available storage capacity to ensure data resiliency. In an RF2 setup, each piece of data is stored on two different nodes to provide redundancy. Once the storage utilization reaches around 81%, the cluster begins to approach its limits in terms of available storage space for continued data operations and redundancy.

If the utilization is at 81%, the remaining capacity for new data is quite limited. In the event of a node failure, there may not be enough free space to replicate data from the failed node across the remaining nodes. This lack of available storage jeopardizes the cluster’s ability to maintain data integrity and ensure continued operations, especially during hardware failures.

Thus, the cluster is deemed not resilient since it cannot adequately handle a node failure due to the high storage utilization, which increases the risk of data loss. Therefore, the situation where the cluster reaches or exceeds this storage threshold can lead to compromised data protection mechanisms, making the cluster vulnerable to failures.