Partition Layout

Recommended Layout

This is the layout used on the reference system (dual-boot with macOS):

Partition	Size	Filesystem	Mount	Purpose
nvme0n1p1	300 MB	FAT32	/boot	EFI System Partition (shared with macOS)
nvme0n1p2	Remaining	BTRFS	/	CachyOS root

Single macOS EFI partition

The MacBook Air 2020 uses a single EFI partition shared between macOS and Linux bootloaders. Limine installs its EFI binary alongside the Apple one — they coexist safely.

BTRFS Subvolumes

The CachyOS installer creates the following BTRFS subvolume layout by default:

nvme0n1p2 (BTRFS pool)
├── @           → /
├── @home       → /home
├── @pkg        → /var/cache/pacman/pkg
├── @log        → /var/log
└── @snapshots  → /.snapshots

Recommended Mount Options

After install, update /etc/fstab BTRFS entries to use these options for better performance on NVMe:

UUID=<uuid>  /  btrfs  noatime,compress=zstd:1,space_cache=v2,autodefrag,discard=async,subvol=@  0 0

Key options explained:

• noatime — don't write file access times (significant NVMe write reduction)
• compress=zstd:1 — transparent compression, level 1 (fast, good ratio)
• space_cache=v2 — faster free-space lookup
• autodefrag — automatic background defragmentation for small files
• discard=async — asynchronous TRIM (much lower latency than discard=sync)

ZRAM Swap

The reference system uses ZRAM instead of a swap partition:

/dev/zram0   15.4G   zstd compression

No swap partition is needed. ZRAM is configured automatically by zram-generator. Verify:

zramctl
swapon --show