A SQL cluster unable to failover or start its services indicates a critical issue. Potential causes include network problems, storage failures, cluster configuration errors, or SQL Server service-specific problems.
Initial Steps:
- Check Cluster Health: Verify all nodes are online and communicating. Inspect the cluster network and storage resources for issues.
- Review Event Logs: Examine Windows and SQL Server logs for error messages related to the failover attempt or service startup.
- Validate Cluster Configuration: Run a cluster validation report to identify potential configuration issues.
- Check SQL Service Dependencies: Ensure all necessary services (like SQL Server Agent, Browser, etc.) are started and dependent on the SQL Server service.
- Verify Disk Configuration: Confirm that all disk resources are online, accessible, and properly configured in the cluster.
- Test Network Connectivity: Verify network connectivity between cluster nodes and the SQL Server instance.
Potential Issues and Solutions:
- Network Problems: If network connectivity is disrupted, failover and service startup will fail. Check network adapters, cables, switches, and firewalls.
- Storage Failures: Disk failures or resource group issues can prevent failover. Check disk status, rebuild failed disks, and verify resource group configuration.
- Cluster Configuration Errors: Incorrectly configured cluster resources or dependencies can cause problems. Review cluster configuration and run validation tests.
- SQL Server Service Issues: Issues with SQL Server service startup might be due to configuration errors, resource conflicts, or file system permissions. Check service configuration, resolve conflicts, and verify permissions.
Additional Considerations:
- Manual Failover: If automatic failover is not working, try a manual failover to isolate the issue.
- Third-Party Tools: Consider using specialized tools for cluster and SQL Server troubleshooting.
- Support Involvement: If the issue persists, contact Microsoft SQL Server support for assistance.
By systematically addressing these areas, you can increase the chances of resolving the SQL cluster failover and service start issues effectively.