BTRFS
Reference for the BTRFS copy-on-write filesystem: subvolumes, snapshots, multi-device and RAID profiles, scrub, compression, qgroups, mount options, and troubleshooting.
Raid
mdadm
Reference for managing Linux software RAID arrays with mdadm and the kernel md driver: creating arrays, persistent configuration, monitoring, disk failure recovery, write-intent bitmaps, and troubleshooting.
RAID
Reference for RAID levels 0, 1, 5, 6, and 10: redundancy, performance, hardware vs software RAID, rebuild and URE risk, scrubbing, cost comparison, and troubleshooting.
ZFS
Reference for OpenZFS on Linux covering pool creation, datasets, snapshots, send/receive replication, RAID-Z, ARC tuning, scrub/resilver, properties, and troubleshooting.