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Many database workloads are sensitive to storage performance. In this best practice, we changed the virtual machine latency sensitivity to optimize performance.
Category | PowerMax Storage |
Product | VMware vSphere Virtual Machines |
Type of best practice | Performance Optimization |
Day and value | Day 3, Fine-tuning |
Overview
VMware vSphere provides the ability to adjust latency sensitivity to optimize low latency database workloads and similar applications. We used the default value for latency sensitivity (Normal) for our baseline test. The default latency sensitivity optimizes storage performance for throughput.
This best practice recommends changing the latency sensitivity to High. Changing the latency sensitivity to High causes ESXi to optimize I/O operations for improved storage latency. This change was completed for all the virtual databases.
Recommendation
Changing the latency sensitivity for the virtualized databases showed no improvement for these performance metrics:
Although there were no significant performance gains in our validation tests, this does not mean that other workloads would not benefit from setting the VM latency sensitivity to High. In these tests, we set all the database latency sensitivities to High. This ensured that all databases were configured the same way, which is not how most systems are configured. Ideally, there will only be a few critical systems with a latency sensitivity setting of High, and others that are set to a Normal or Low setting. This combination could yield a greater performance gain for the production systems.
We recommend virtual machine latency sensitivity as a Day 3, Fine-tuning activity. Consider changing the latency sensitivity to High for the Oracle production virtual machines to optimize storage performance.
Implementation Steps
Requirements:
ESXi 6.7 requires full CPU reservation to power on a VM with hardware version 14 when latency sensitivity is set to High. For more information, see Adjust Latency Sensitivity.
Additional Resources