Local Store

Store URL format: local, root

This store type accesses a Nix store in the local filesystem directly (i.e. not via the Nix daemon). root is an absolute path that is prefixed to other directories such as the Nix store directory. The store pseudo-URL local denotes a store that uses / as its root directory.

A store that uses a root other than / is called a chroot store. With such stores, the store directory is "logically" still /nix/store, so programs stored in them can only be built and executed by chroot-ing into root. Chroot stores only support building and running on Linux when mount namespaces and user namespaces are enabled.

For example, the following uses /tmp/root as the chroot environment to build or download nixpkgs#hello and then execute it:

# nix run --store /tmp/root nixpkgs#hello
Hello, world!

Here, the "physical" store location is /tmp/root/nix/store, and Nix's store metadata is in /tmp/root/nix/var/nix/db.

It is also possible, but not recommended, to change the "logical" location of the Nix store from its default of /nix/store. This makes it impossible to use default substituters such as https://cache.nixos.org/, and thus you may have to build everything locally. Here is an example:

# nix build --store 'local?store=/tmp/my-nix/store&state=/tmp/my-nix/state&log=/tmp/my-nix/log' nixpkgs#hello

Settings

  • log

    directory where Nix will store log files.

    Default: /nix/var/log/nix

  • path-info-cache-size

    Size of the in-memory store path metadata cache.

    Default: 65536

  • priority

    Priority of this store when used as a substituter. A lower value means a higher priority.

    Default: 0

  • read-only

    Allow this store to be opened when its database is on a read-only filesystem.

    Normally Nix will attempt to open the store database in read-write mode, even for querying (when write access is not needed), causing it to fail if the database is on a read-only filesystem.

    Enable read-only mode to disable locking and open the SQLite database with the immutable parameter set.

    Warning Do not use this unless the filesystem is read-only.

    Using it when the filesystem is writable can cause incorrect query results or corruption errors if the database is changed by another process. While the filesystem the database resides on might appear to be read-only, consider whether another user or system might have write access to it.

    Default: false

  • real

    Physical path of the Nix store.

    Default: /nix/store

  • require-sigs

    Whether store paths copied into this store should have a trusted signature.

    Default: true

  • root

    Directory prefixed to all other paths.

    Default: ``

  • state

    Directory where Nix will store state.

    Default: /dummy

  • store

    Logical location of the Nix store, usually /nix/store. Note that you can only copy store paths between stores if they have the same store setting.

    Default: /nix/store

  • system-features

    Optional system features available on the system this store uses to build derivations.

    Example: "kvm"

    Default: machine-specific

  • trusted

    Whether paths from this store can be used as substitutes even if they are not signed by a key listed in the trusted-public-keys setting.

    Default: false

  • want-mass-query

    Whether this store can be queried efficiently for path validity when used as a substituter.

    Default: false