How Linux Bcache Caches Block Devices for Speed

Episode 155 of The Linux Podcast dives into Bcache, the Linux kernel block-layer caching that lets you put a fast SSD in front of slow spinning disks. Lucas and Luna walk through how Bcache works at the block level, why it's different from filesystem-level caching, and where it shines—like speeding up database storage or home lab NAS builds without ripping out existing drives. They break down the key concepts: caching modes (writeback, writethrough, writearound), the bucket and priority cache structure, and how to attach a cache device to a backing device. They also touch on real-world performance numbers, like how Bcache can slash read latency from tens of milliseconds to under a millisecond for hot data, and discuss the trade-offs, including writeback risks and the importance of a UPS. The episode wraps with a look at Bcachefs, the next-gen filesystem that builds on Bcache's ideas, and a practical tip for anyone considering Bcache in their own setup. If you've ever wanted to squeeze more life out of old hard drives, this is the episode for you. #Bcache #Linux #BlockCaching #SSD #HDD #Storage #Kernel #Filesystem #Bcachefs #NAS #HomeLab #Performance #Writeback #Writethrough #Technology #OpenSource #FexingoBusiness #BusinessPodcast Keep every episode free: buymeacoffee.com/fexingo