subvolNAME

subvolNAME is a subvolume within a Btrfs filesystem. In Btrfs, a subvolume is an independently addressable namespace inside a single volume that can be mounted separately, snapshotted, and managed with quotas. SubvolNAME exists as a directory-like entry in the Btrfs tree and shares the same pool of disk space with other subvolumes on the filesystem.

Creation and management: Subvols are created with the btrfs subvolume create command, for example "btrfs subvolume create /path/to/subvolNAME". The subvolume forms its own root within the filesystem and can be listed with "btrfs subvolume list /mount". Data within a subvolume is managed by the same CoW and checksums rules that govern the rest of the Btrfs filesystem.

Mounting and use: To mount a specific subvolume, use the subvol option, such as "mount -o subvol=subvolNAME /dev/sdXn /mnt/subvolNAME" or configure it in fstab. SubvolNAME can be mounted at a dedicated mount point or bound to other paths as needed. This allows logical separation of data, system roots, or application data within a single physical disk.

Snapshots and backups: SubvolNAME can be snapshotted to capture a point-in-time state, using commands like "btrfs subvolume snapshot create" or "btrfs subvolume snapshot create -r" for read-only snapshots. Snapshots are lightweight and share data until modified due to copy-on-write behavior.

Storage management: Btrfs supports quotas and other features (compression, checksums, dedup) that can be applied to subvolNAME via mount options and quota tools. Subvols enable isolation and flexible management while remaining part of the same filesystem. Typical uses include system partitions, application data separation, containers, and backup workflows.