The decision to change the storage pool granularity was based on LiveOptics output, which is a tool for workload characterization. Fine granularity (1 MB chunks) is optimal for workloads with small, random I/Os, such as databases. Medium granularity (4 MB chunks) is better suited for general-purpose workloads or those with larger I/O sizes. By analyzing the LiveOptics data, the architect determined the actual workload was better aligned with medium granularity. This change optimizes the I/O path and reduces processing overhead for the prevalent I/O size, resulting in improved overall performance.

1. Dell PowerFlex: Best Practices Guide (Version 3.6)

Page 18

Section: "Storage Pools": "Fine granularity is recommended for database workloads that have small I/O sizes... Medium granularity is recommended for most other workloads

including hyperconverged deployments." This directly links the choice of granularity to workload type for performance optimization.

2. Dell PowerFlex: Architecture and Concepts Guide (Version 4.x)

Section: "Logical architecture"

Subsection: "Storage Pool": This document explains that the system divides storage into chunks of either 1 MB (Fine) or 4 MB (Medium). Aligning this chunk size with the application's typical I/O size is a key performance tuning principle. The guide also details the metadata overhead

confirming that medium granularity has lower overhead

which supports the reasoning for why option C is a secondary effect.