A customer has a 4-node cluster. Two nodes have FlashCache and the other two nodes have Flash Pools. The customer is interested in deploying and OLTP application with a workload that consists of an…

Flash Pool hybrid aggregates use SSDs as both a read and write cache tier, meaning small random writes are absorbed by the SSD layer and destaged to spinning disk asynchronously, dramatically reducing write latency for OLTP workloads. FlashCache cards, by contrast, function as an intelligent read cache only and do not accelerate random write operations, making Flash Pool the correct placement for all four write-intensive volumes.

FlashCache (Performance Acceleration Module) is a read cache that caches frequently accessed blocks in flash memory on the controller - it does not provide a write caching tier, so it offers no benefit for write-intensive OLTP workloads.

Splitting volumes between FlashCache and Flash Pool nodes gives only half the volumes the benefit of SSD write caching, unnecessarily leaving the FlashCache-hosted volumes without write acceleration.

Routing only the highest read-load volume to Flash Pool nodes ignores the stated workload characteristic of extreme random writes across all four volumes, leaving most of the write workload without SSD-backed write caching.