Input/Output Operations Per Second (IOPS), Path Policy, and Multipathing are all important considerations for storage performance and stability in a virtualized environment. In this blog post, we'll cover some best practices for setting IOPS, Path Policy, and Multipathing for storage, and provide a script for changing these settings on multiple datastores in vCenter.
Multipathing in ESXi
Multipathing is a technique used to provide redundancy and load balancing for storage devices. In ESXi, multipathing is achieved by using multiple paths between the ESXi host and the storage device. This can help to increase performance and reliability by providing alternate paths in case of failure or congestion.
Before setting IOPS and Path Policy limits for storage, it's important to understand the specific storage technology used and the workload characteristics. Workload characteristics, such as read/write ratios, block sizes, and access patterns, can affect the optimal settings.
To determine the optimal settings for storage, it's recommended to consult with your storage vendor or refer to their documentation. The vendor may have specific recommendations for the settings based on the specific storage technology being used and the workload characteristics. The documentation may also provide guidance on how to measure and monitor performance to ensure optimal performance and stability.
Perform Thorough Testing
Once you've determined the optimal settings for storage based on vendor recommendations or documentation, it's important to perform thorough testing before making any changes in a production environment. This can involve using benchmarking tools or simulating workload scenarios to measure the impact of changing the limits on performance and stability. It's also recommended to test changes in a non-production environment first to minimize the risk of unexpected issues in production.
Consider Latency and Contention for Resources
Setting high limits may not always result in better performance, and may actually increase latency due to contention for resources. It's important to consider the overall workload and resource usage when setting the limits to ensure sufficient capacity to meet the demands of the workload without introducing latency or resource contention issues.
Changing IOPS and Path Policy Settings with PowerCLI
Here is a command for changing the IOPS and Path Policy settings on data stores in vCenter using PowerCLI:
Thanks,
Siddartha Kumar Das