* Added a global configuration file (/nix/etc/nix/nix.conf). It

  contains options for the garbage collector right now, but other
  stuff can be added here later.

1 files changed, 30 insertions, 0 deletions

diff --git a/nix.conf.example b/nix.conf.example
new file mode 100644
index 000000000000..1af5df952b37
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+++ b/nix.conf.example
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+### Option `gc-keep-outputs'
+#
+# If `true', the garbage collector will keep the outputs of
+# non-garbage derivations.  If `false' (default), outputs will be
+# deleted unless they are GC roots themselves (or reachable from other
+# roots).
+# 
+# In general, outputs must be registered as roots separately.
+# However, even if the output of a derivation is registered as a root,
+# the collector will still delete store paths that are used only a
+# build time (e.g., the C compiler, or source tarballs downloaded from
+# the network).  To prevent it from doing so, set this option to
+# `true'.
+gc-keep-outputs = false
+
+
+### Option `gc-keep-derivations'
+#
+# If `true' (default), the garbage collector will keep the derivations
+# from which non-garbage store paths were built.  If `false', they
+# will be deleted unless explicitly registered as a root (or reachable
+# from other roots).
+#
+# Keeping derivation around is useful for querying and traceability
+# (e.g., it allows you to ask with what dependencies or options a
+# store path was built), so by default this option is on.  Turn it off
+# to safe a bit of disk space (or a lot if `gc-keep-outputs' is also
+# turned on).
+gc-keep-derivations = true
+