Building a new SQL cluster in vCenter requires careful planning and consideration of several factors. Here’s a comprehensive guide covering prerequisites, questions to ask the customer, and recommendations for a highly utilized SQL cluster.
- Hardware Resources: Ensure that the host servers have adequate CPU, memory, and storage resources to handle the expected workload. Consider the growth projections and ensure scalability.
- Networking: Verify that the network infrastructure can support the required bandwidth and latency for SQL cluster communication. Plan for redundancy and fault tolerance with multiple network interfaces.
- Storage Configuration: Choose a storage solution with sufficient capacity, performance, and redundancy for the SQL cluster. Consider options like Fibre Channel, iSCSI, or NFS, depending on the requirements and capabilities of your environment.
- vCenter and ESXi Version Compatibility: Ensure that the vCenter Server and ESXi hosts are compatible with the version of SQL Server you plan to deploy. Check the VMware Compatibility Guide for compatibility information.
- Cluster Quorum: Decide on the cluster quorum configuration, which determines how the cluster makes decisions in case of node failures. Options include a shared disk, a witness server, or a file share witness.
Questions to Ask the Customer:
- Workload Requirements: Understand the specific workload characteristics, such as the number of concurrent users, database size, IOPS (Input/Output Operations Per Second) requirements, and expected growth rate. This information helps determine the necessary hardware resources.
- High Availability Requirements: Determine the desired level of availability, including considerations for failover and disaster recovery. Discuss the Recovery Point Objective (RPO) and Recovery Time Objective (RTO) to determine the appropriate cluster configuration.
- Backup and Recovery Strategy: Inquire about the customer’s backup and recovery strategy for the SQL cluster. Understand their preferred backup solution and any specific requirements that may impact the cluster design.
- Security Considerations: Discuss security requirements such as network segmentation, firewall rules, encryption, and authentication mechanisms to ensure that the SQL cluster meets the necessary security standards.
Recommendations for a Highly Utilized SQL Cluster:
- Disk Configuration: Consider using VMware’s paravirtualized SCSI adapter (PVSCSI) for improved disk performance. Deploying multiple virtual disks spread across different storage LUNs can help distribute I/O load and enhance performance.
- Disk Mode: Choose the appropriate disk mode based on the customer’s requirements. For maximum performance, use “Independent – Persistent” mode. If application-level consistency is important, use “Independent – Nonpersistent” mode along with a suitable backup strategy.
- VMDK Disk File Format: Use the VMFS6 file format for improved performance and scalability. VMFS6 supports features like automatic space reclamation and supports larger VMDK sizes.
- vCPU Configuration: It is generally recommended to use fewer sockets and more cores per socket. This configuration provides better scalability, NUMA optimization, and reduces potential NUMA contention. However, consult the SQL Server licensing requirements to ensure compliance with the core-based licensing model.
- vNUMA: If the host server has NUMA architecture, enable vNUMA in the VM’s settings. This allows the VM’s vCPUs and memory to align with the NUMA nodes, optimizing performance and reducing memory latency.
- vCPU Hot Plug: Disable vCPU hot plug for SQL Server VMs. Hot plug operations can cause a temporary performance impact and are generally not recommended for critical database workloads.
- Monitoring and Optimization: Implement performance monitoring tools to keep track of SQL Server performance metrics, including CPU utilization, disk I/O, memory usage, and network latency. Regularly review these metrics to identify performance bottlenecks and optimize the cluster configuration as needed.