Optane menory is a really nice solution for write-back caches to slow HDDs (e.g. ZFS Slog, bcache, ...). Or a cache for often-requested HDD blocks which didn't

Optane menory is a really nice solution for write-back caches to slow HDDs (e.g. ZFS Slog, bcache, ...). Or a cache for often-requested HDD blocks which didn't fit anymore to RAM (ZFS L2ARC).