Air cooling is not efficient enough to support ultra high density. With this in mind, we adapted direct liquid cooling to our air-cooling rack: specific higher power server components such as CPUs and GPUs are exposed to liquid in order to be cooled more efficiently than air cooling. Highest performance servers can be integrated efficiently using this approach. Our DLC rack includes manifolds with double shut-off valves to ensure hot-swappable liquid distribution to the servers at the rear of the rack. In addition to the DLC, 9 fans ensure to keep remaining components cool to avoid SPOFs (Single Point Of Failure).