Btrfs Subvolume

Btrfs subvolumes provide native, kernel-level per-server disk limits with no user-space overhead. Each server's data directory is placed in its own Btrfs subvolume, and the quota is enforced by the kernel's Btrfs quota group (qgroup) system.

Requirements

• Host filesystem must be formatted as Btrfs
• The Wings server data directory (/var/lib/pterodactyl/volumes by default) must reside on the Btrfs filesystem
• Btrfs tools: btrfs-progs package

How It Works

When Wings creates a server, it creates a Btrfs subvolume at the server's data path and assigns a qgroup with the configured disk limit. The kernel enforces the limit natively - no daemon processes, no FUSE overhead.

Setup

1. Verify Btrfs Filesystem

findmnt -T /var/lib/pterodactyl

The FSTYPE column should show btrfs. If it shows ext4 or another type, Btrfs subvolumes are not available on this mount.

2. Enable Btrfs Quotas

btrfs quota enable /var/lib/pterodactyl

3. Configure Wings

In /etc/pterodactyl/config.yml:

system:
  disk_limiter_mode: btrfs_subvolume

Restart Wings after applying the change.

Migrating Existing Servers

Existing server data directories are plain directories, not subvolumes. To migrate:

1. Stop the server in the Panel
2. Convert the directory to a subvolume:

   mv /var/lib/pterodactyl/volumes/<uuid> /var/lib/pterodactyl/volumes/<uuid>.bak
   btrfs subvolume create /var/lib/pterodactyl/volumes/<uuid>
   cp -a /var/lib/pterodactyl/volumes/<uuid>.bak/. /var/lib/pterodactyl/volumes/<uuid>/
   rm -rf /var/lib/pterodactyl/volumes/<uuid>.bak

3. Start the server

Wings will automatically assign a qgroup on next start.