BTRFS
Reference for the BTRFS copy-on-write filesystem: subvolumes, snapshots, multi-device and RAID profiles, scrub, compression, qgroups, mount options, and troubleshooting.
Filesystem
Filesystem Creation
Guide to partitioning disks with fdisk and parted, creating ext4/XFS/Btrfs/FAT32 filesystems, setting up swap and UEFI boot partitions, and configuring persistent mounts via fstab.
ZFS
Reference for OpenZFS on Linux covering pool creation, datasets, snapshots, send/receive replication, RAID-Z, ARC tuning, scrub/resilver, properties, and troubleshooting.