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NVMe scratch — the working set, and nothing else
Local or fabric-attached NVMe, sized to hold one job's working set with headroom for checkpoints. Microsecond-class latency, the highest cost per terabyte in the estate, and no resilience guarantee anyone should rely on. Scratch is purged by the scheduler epilogue. We write that into the Slurm job template and the user documentation. The first person to leave a thesis in scratch should learn the rule from a wiki page, not from a purge.