CassandraClientRequestReadFailure

CassandraClientRequestReadFailure #

Read failures have occurred, ensure there are not too many unavailable nodes - {{ $labels.cassandra_cluster }}

Alert Rule
alert: CassandraClientRequestReadFailure
annotations:
  description: |-
    Read failures have occurred, ensure there are not too many unavailable nodes - {{ $labels.cassandra_cluster }}
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/instaclustr-cassandra-exporter/cassandraclientrequestreadfailure/
  summary: Cassandra client request read failure (instance {{ $labels.instance }})
expr: increase(cassandra_client_request_failures_total{operation="read"}[1m]) > 0
for: 2m
labels:
  severity: critical

Here is the runbook for the CassandraClientRequestReadFailure alert:

Meaning #

The CassandraClientRequestReadFailure alert is triggered when there is an increase in the total number of Cassandra client request read failures over a 1-minute period. This alert indicates that there are issues with reading data from Cassandra, which can impact the performance and reliability of dependent applications.

Impact #

The impact of this alert can be significant, as it can lead to:

  • Data inconsistencies and loss
  • Performance degradation of dependent applications
  • Increased latency and errors
  • Potential data loss or corruption

Diagnosis #

To diagnose the root cause of the CassandraClientRequestReadFailure alert, perform the following steps:

  1. Check the Cassandra cluster health and node status to identify any unavailable nodes or nodes with high latency.
  2. Review the Cassandra client request logs to identify any patterns or trends in the read failures.
  3. Verify that the Cassandra cluster is properly configured and that there are no issues with data replication or consistency.
  4. Check the system resources (CPU, memory, disk space) of the Cassandra nodes to ensure they are not overloaded.
  5. Review the network connectivity and firewall rules to ensure there are no issues with communication between the Cassandra nodes and clients.

Mitigation #

To mitigate the CassandraClientRequestReadFailure alert, perform the following steps:

  1. Investigate and address any underlying issues with the Cassandra cluster, such as node failures or network connectivity problems.
  2. Implement retries and fallback mechanisms in the application to handle temporary read failures.
  3. Consider increasing the number of replicas or improving data replication to reduce the impact of node failures.
  4. Optimize the Cassandra client configuration to improve performance and reduce the likelihood of read failures.
  5. Perform regular maintenance and upgrades to ensure the Cassandra cluster is running with the latest software and configurations.

By following these steps, you can identify and address the root cause of the CassandraClientRequestReadFailure alert and ensure the reliability and performance of your Cassandra cluster.

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