Rdma

DeepSeek V4 Flash needs more memory than one DGX Spark has. This guide splits it across two Sparks with vLLM tensor parallelism over RoCE, reaches 51 tokens per second, and connects OpenAI’s Codex CLI as a fully local coding agent.

Two snapshots of Longhorn’s SPDK-based v2 engine on the same three Ampere nodes: 1.12 with my RDMA patches, then 1.14 development builds with a newer SPDK. NVMe/TCP got about 7× lower write latency and now fills a 25 GbE link. RDMA still halves write latency.