diff --git a/doc/manual/installation/installing-binary.xml b/doc/manual/installation/installing-binary.xml index 3f57f47b5..86cbce6bf 100644 --- a/doc/manual/installation/installing-binary.xml +++ b/doc/manual/installation/installing-binary.xml @@ -136,6 +136,109 @@ sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist +
+ APFS Volume Installation + + + The root filesystem is read-only as of macOS 10.15 Catalina, all writable + paths to a separate data volume. This means creating or writing to /nix + is not allowed. While changing the default prefix would be possible, it's + a very intrusive change that has side effects we want to avoid for now. + + + + For common writable locations firmlinks where introduced, + described by Apple as a "bi-directional wormhole" between two filesystems. + Essentially a bind mount for APFS volumes. However this is (currently) not + user configurable and only available for paths like /Users. + + + + For special cases like NFS mount points or package manager roots synthetic.conf(5) + provides a mechanism for some limited, user-controlled file-creation at /. + This only applies on a reboot, but apfs.util can be used + to trigger the creation (not deletion) of new entries. + + + +alice$ /System/Library/Filesystems/apfs.fs/Contents/Resources/apfs.util -B + + + + + + The simplest solution is creating a symlink with /etc/synthetic.conf + to the data volume. (not recommended) + + + +nix /System/Volumes/Data/nix + + + +alice$ ls -l / +lrwxr-xr-x 1 root wheel 25 Jan 1 2019 nix -> /System/Volumes/Data/nix + + + + However builds that detect or resolve this symlink will leak the canonical + location or even fail in certain cases, making this approach undesirable. + + + + + + An empty directory can also be created using /etc/synthetic.conf, + this won't be writable but can be used as a mount point. And with + APFS it's relatively easy to create an separate + volume for nix instead. + + + +nix + + + +alice$ sudo diskutil apfs addVolume diskX APFS 'Nix Store' -mountpoint /nix +alice$ mount +/dev/disk1s6 on /nix (apfs, local, journaled) + + + + This does make the installation more complicated, requiring both + /etc/synthetic.conf as well as /etc/fstab + + + +# +# Warning - this file should only be modified with vifs(8) +# +# Failure to do so is unsupported and may be destructive. +# +LABEL=Nix\040Store /nix apfs rw + + + + On macOS volumes are also mounted quite late, launchd services or other + things that start during login will start before our volume is mounted. + For these cases eg. wait4path must be used for + things that depend on /nix. + + + + This new volume also won't be encrypted by default, and enabling is + only possible interactively? + + + +diskutil apfs enableFileVault /nix -user disk + + + + + +
+
Installing a pinned Nix version from a URL