Multiple devices

bcachefs is a multi-device filesystem. Devices need not be the same size: by default, the allocator will stripe across all available devices but biasing in favor of the devices with more free space, so that all devices in the filesystem fill up at the same rate. Devices need not have the same performance characteristics: we track device IO latency and direct reads to the device that is currently fastest.

• Replication
• Erasure coding
• Device labels and targets
• Caching
• Durability