I’m attempting a new install. I want to use btrfs with swapfile.
Do I need to disable compression on my swap subvolume?
Is there anything else I should keep in mind for fstab if I want to, say, not keep track of my Downloads folder when snapshotting?
Here is my fstab:
LABEL=arch@btrfs / btrfs rw,relatime,discard=async,space_cache=v2,subvolid=256,subvol=>
LABEL=arch@btrfs /home btrfs rw,relatime,discard=async,space_cache=v2,subvolid=257,subvol=>
LABEL=arch@btrfs /var/cache/pacman/pkg btrfs rw,relatime,discard=async,space_cache=v2,subvolid=259>
LABEL=arch@btrfs /var/log btrfs rw,relatime,discard=async,space_cache=v2,subvolid=258,subvol=>
LABEL=arch@btrfs /.snapshots btrfs rw,relatime,discard=async,space_cache=v2,subvolid=260,subvol=>
LABEL=arch@btrfs /swap btrfs rw,relatime,discard=async,space_cache=v2,subvolid=263,subvol=>
LABEL=efi@fat32 /efi vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=asci>
/swap/swapfile none swap defaults 0 0
Short: No
Long: it doesn’t matter when mounting multiple subvolumes of the same btrfs partition the options from the first one (usually /) will apply to all. So even if you disable it, that will be ignored.
The old way of creating swap shows the chattr +C line which disables CoW. The same method should work for your Downloads folder since CoW is needed for snapshotting.