* GC docs.

This commit is contained in:
Eelco Dolstra 2005-04-07 08:17:04 +00:00
parent 128c174295
commit 806b91f104
3 changed files with 112 additions and 177 deletions

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@ -1,77 +1,29 @@
<refentry>
<refnamediv>
<refname>nix-collect-garbage</refname>
<refpurpose>remove unreachable store paths</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>nix-collect-garbage</command>
<group choice='opt'>
<arg choice='plain'><option>--print-live</option></arg>
<arg choice='plain'><option>--print-dead</option></arg>
</group>
<arg><option>--min-age</option> <replaceable>age</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refnamediv>
<refname>nix-collect-garbage</refname>
<refpurpose>delete unreachable store paths</refpurpose>
</refnamediv>
<refsection>
<title>Description</title>
<refsynopsisdiv>
<cmdsynopsis>
<command>nix-collect-garbage</command>
<group choice='opt'>
<arg choice='plain'><option>--print-roots</option></arg>
<arg choice='plain'><option>--print-live</option></arg>
<arg choice='plain'><option>--print-dead</option></arg>
<arg choice='plain'><option>--delete</option></arg>
</group>
</cmdsynopsis>
</refsynopsisdiv>
<para>
The command <command>nix-collect-garbage</command> performs a
garbage collection on the Nix store: any paths in the Nix store
that are garbage (not reachable from a set of root store
expressions) are deleted.
</para>
<refsection><title>Description</title>
<para>
The roots of the garbage collector are the store expressions
mentioned in the files in the directory
<filename><replaceable>prefix</replaceable>/var/nix/gcroots</filename>.
By default, the roots are all user environments in
<filename><replaceable>prefix</replaceable>/var/nix/profiles</filename>.
You can register other store expressions as roots by writing the
full path of the store expression to an arbitrary file in the
<filename>gcroots</filename> directory (or a subdirectory
thereof).
</para>
<para>The command <command>nix-collect-garbage</command> is an
obsolete wrapper around <link
linkend="rsec-nix-store-gc"><command>nix-store
--gc</command></link>.</para>
</refsection>
<refsection>
<title>Options</title>
<variablelist>
<varlistentry>
<term><option>--print-live</option> / <option>--print-dead</option></term>
<listitem>
<para>
These options cause the set of live or dead paths to be
printed, respectively, rather than performing an actual
garbage collector. They correspond exactly with the
sub-operations in <command>nix-store
<option>--gc</option></command>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Examples</title>
<para>
To delete all unreachable paths, just do:
<screen>
$ nix-collect-garbage</screen>
</para>
</refsection>
</refsection>
</refentry>

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@ -146,126 +146,121 @@ output.</para>
<!--######################################################################-->
<refsection>
<title>Operation <option>--gc</option></title>
<refsection id='rsec-nix-store-gc'><title>Operation <option>--gc</option></title>
<refsection>
<title>Synopsis</title>
<cmdsynopsis>
<command>nix-store</command>
<arg choice='plain'><option>--gc</option></arg>
<group choice='req'>
<arg choice='plain'><option>--print-live</option></arg>
<arg choice='plain'><option>--print-dead</option></arg>
<arg choice='plain'><option>--delete</option></arg>
</group>
<arg><option>--min-age</option> <replaceable>age</replaceable></arg>
</cmdsynopsis>
</refsection>
<refsection><title>Synopsis</title>
<refsection>
<title>Description</title>
<cmdsynopsis>
<command>nix-store</command>
<arg choice='plain'><option>--gc</option></arg>
<group choice='req'>
<arg choice='plain'><option>--print-roots</option></arg>
<arg choice='plain'><option>--print-live</option></arg>
<arg choice='plain'><option>--print-dead</option></arg>
<arg choice='plain'><option>--delete</option></arg>
</group>
</cmdsynopsis>
<para>
Without additional flags, the operation <option>--gc</option>
performs a garbage collection on the Nix store. That is, all
paths in the Nix store not reachable via file system
references from a set of <quote>roots</quote>, are deleted.
</para>
</refsection>
<para>
The following flags may be specified:
</para>
<refsection><title>Description</title>
<variablelist>
<para>Without additional flags, the operation <option>--gc</option>
performs a garbage collection on the Nix store. That is, all paths in
the Nix store not reachable via file system references from a set of
<quote>roots</quote>, are deleted.</para>
<varlistentry>
<term><option>--print-roots</option></term>
<listitem>
<para>
This operation prints on standard output the set of
roots used by the garbage collector.
</para>
</listitem>
</varlistentry>
<para>The following suboperations may be specified:</para>
<varlistentry>
<term><option>--print-live</option></term>
<listitem>
<para>
This operation prints on standard output the set of
<quote>live</quote> store paths, which are all the store
paths reachable from the roots. Live paths should never
be deleted, since that would break consistency — it
would become possible that applications are installed
that reference things that are no longer present in the
store.
</para>
</listitem>
</varlistentry>
<variablelist>
<varlistentry>
<term><option>--print-dead</option></term>
<listitem>
<para>
This operation prints out on standard output the set of
<quote>dead</quote> store paths, which is just the
opposite of the set of live paths: any path in the store
that is not live (with respect to the roots) is dead.
</para>
</listitem>
</varlistentry>
<varlistentry><term><option>--print-roots</option></term>
<varlistentry>
<term><option>--delete</option></term>
<listitem>
<para>
This operation performs an actual garbage collection.
All dead paths are removed from the store.
</para>
</listitem>
</varlistentry>
<listitem><para>This operation prints on standard output the set
of roots used by the garbage collector.</para></listitem>
</variablelist>
</varlistentry>
</refsection>
<varlistentry><term><option>--print-live</option></term>
<refsection>
<title>Roots</title>
<listitem><para>This operation prints on standard output the set
of <quote>live</quote> store paths, which are all the store paths
reachable from the roots. Live paths should never be deleted,
since that would break consistency — it would become possible that
applications are installed that reference things that are no
longer present in the store.</para></listitem>
<para>The roots of the garbage collector are all store paths to
which there are symlinks in the
directory <filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>.
For instance, the following command makes the
path <filename>/nix/store/d718ef...-foo</filename> a root of
the collector:
</varlistentry>
<varlistentry><term><option>--print-dead</option></term>
<listitem><para>This operation prints out on standard output the
set of <quote>dead</quote> store paths, which is just the opposite
of the set of live paths: any path in the store that is not live
(with respect to the roots) is dead.</para></listitem>
</varlistentry>
<varlistentry><term><option>--delete</option></term>
<listitem><para>This operation performs an actual garbage
collection. All dead paths are removed from the
store. This is the default.</para></listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection><title>Roots</title>
<para>The roots of the garbage collector are all store paths to which
there are symlinks in the directory
<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>.
For instance, the following command makes the path
<filename>/nix/store/d718ef...-foo</filename> a root of the collector:
<screen>
$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar</screen>
That is, after this command, the garbage collector will not
remove <filename>/nix/store/d718ef...-foo</filename> or any of
its dependencies.</para>
That is, after this command, the garbage collector will not remove
<filename>/nix/store/d718ef...-foo</filename> or any of its
dependencies.</para>
<para>Subdirectories
of <filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>
are also searched for symlinks. Symlinks to non-store paths are
followed and searched for roots, but TODO.</para>
<para>Subdirectories of
<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>
are also searched for symlinks. Symlinks to non-store paths are
followed and searched for roots, but TODO.</para>
</refsection>
</refsection>
<refsection>
<title>Configuration file</title>
<para>TODO</para>
<refsection><title>Configuration file</title>
</refsection>
<para>TODO</para>
</refsection>
</refsection>
<refsection><title>Examples</title>
<para>To delete all unreachable paths, just do:
<screen>
$ nix-store --gc</screen>
</para>
</refsection>
</refsection>
<!--######################################################################-->
<!--######################################################################-->
<refsection>
<title>Operation <option>--query</option></title>
@ -586,10 +581,3 @@ x=`nix-store --query --normalise --force-realise /nix/store/bla.store`
</refentry>
<!--
local variables:
sgml-parent-document: ("book.xml" "refentry")
end:
-->

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