As NVDIMMs enter the realm of standard equipment on servers and storage arrays and NVMe is standard equipment for servers and consumer devices alike, what is the actual performance advantage of using NVDIMM over NVMe, or NVMe over SAS or SATA SSDs? First, we’ll review some purely synthetic benchmarks of single devices using different storage technologies and see how they differ. Then, we’ll enter a more real world environment and see what performance gains can be had.

One use of NVDIMMs is as a transaction log to allow quick acknowledgement of write operations. In our real-world scenario, we discuss the performance differences of using NVDIMMs, NVMe Flash, or SAS/SATA Flash as the SLOG or “write-cache” for an OpenZFS pool.

Learning Objectives: 1) Performance differences between different storage media and storage transports for transactional workloads; 2) Basic overview of OpenZFS and how a SLOG works; 3) Impact of low latency NVDIMM and NVMe storage for application and user latency.