Recipes

Four pools people actually build, with the settings that make each one behave. All assume the install of chapter 3 and the fstab shape of chapter 7.

1. The media library

The job: several drives of films, music and photos behind one folder the media server reads.

branches=/mnt/disk1:/mnt/disk2:/mnt/disk3
category.create=epmfs
minfreespace=20G
moveonenospc=true
allow_other,use_ino
cache.files=partial,dropcacheonclose=true

Why: epmfs keeps a film's folder — and a show's whole run — on one drive (chapter 5); moveonenospc rescues the occasional file still downloading when its drive tops out; read-mostly workloads are where cache.files=partial earns its place. Pair with parity (chapter 10) before the library is bigger than your willingness to re-rip it.

2. The download landing pad

The job: one incoming folder fed by download tools, emptied by whatever sorts the results into libraries.

branches=/mnt/fast:/mnt/spare
category.create=ff
minfreespace=10G
moveonenospc=true

Why: ff fills the fast drive first and only spills to the spare when it must — order matters more than balance here. Keep the sorted libraries out of this pool; the pad is scratch space with good manners, and chapter 9's hard-link notes apply if the sorter links finished files into a library on the same pool.

3. The growing photo archive

The job: a family archive that gains a drive every few years and must never scatter one year's photos across all of them.

branches=/mnt/photos1:/mnt/photos2
category.create=epff
minfreespace=50G

Why: epff — existing-path, then first fit — fills the older drive completely before the new one takes a single new folder, and every folder still lives whole on one drive. When photos1 fills, photos2 inherits the future, not fragments of the past. Back this one up off-box (chapter 10); archives are the files you cannot re-create.

4. The everything drawer

The job: one big unglamorous folder for a household's miscellany — ISOs, installers, exports, "put it in the drawer" — where convenience is the entire point.

branches=/mnt/disk1:/mnt/disk2
category.create=mfs
minfreespace=5G
allow_other

Why: bare mfs spreads by emptiness; nobody cares which drive holds an ISO, and even wear is a small kindness to old drives. The drawer's risk is not placement but amnesia: label it scratch in everyone's mind, and keep anything irreplaceable out of it or backed up from it.

A recipe deliberately missing

There is no "the safe archive" recipe built on mergerfs alone, on purpose. Pools present files; they do not protect them. If a recipe above tempts you to skip chapter 10, reread chapter 10.