* Updated the manual.

This commit is contained in:
Eelco Dolstra 2008-11-19 17:00:32 +00:00
parent e13da525a7
commit 63ccd72496
2 changed files with 134 additions and 3 deletions

View file

@ -128,6 +128,7 @@ lrwxrwxrwx 1 ... 2005-03-13 21:10 /home/eelco/bla/result -> /nix/store/1r1134
<arg choice='plain'><option>-r</option></arg> <arg choice='plain'><option>-r</option></arg>
</group> </group>
<arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg> <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
<arg><option>--dry-run</option></arg>
</cmdsynopsis> </cmdsynopsis>
</refsection> </refsection>
@ -166,6 +167,11 @@ the specified store paths. Realisation is a somewhat overloaded term:
output. (For non-derivations argument, the argument itself is output. (For non-derivations argument, the argument itself is
printed.)</para> printed.)</para>
<para>If the <option>--dry-run</option> option is used, then
<command>nix-store</command> will print on standard error a
description of what packages would be built or downloaded, and then
quit.</para>
</refsection> </refsection>
@ -204,6 +210,10 @@ linkend="sec-nix-build"><command>nix-build</command></link> does.</para>
<arg choice='plain'><option>--print-dead</option></arg> <arg choice='plain'><option>--print-dead</option></arg>
<arg choice='plain'><option>--delete</option></arg> <arg choice='plain'><option>--delete</option></arg>
</group> </group>
<arg><option>--max-freed</option> <replaceable>bytes</replaceable></arg>
<arg><option>--max-links</option> <replaceable>nrlinks</replaceable></arg>
<arg><option>--max-atime</option> <replaceable>atime</replaceable></arg>
<arg><option>--use-atime</option></arg>
</cmdsynopsis> </cmdsynopsis>
</refsection> </refsection>
@ -258,7 +268,70 @@ the Nix store not reachable via file system references from a set of
</variablelist> </variablelist>
<para>The behaviour of the collector is influenced by the <link <para>By default, all unreachable paths are deleted. The following
options control what gets deleted and in what order:
<variablelist>
<varlistentry><term><option>--max-freed</option> <replaceable>bytes</replaceable></term>
<listitem><para>Keep deleting paths until at least
<replaceable>bytes</replaceable> bytes have been
deleted, then stop.</para></listitem>
</varlistentry>
<varlistentry><term><option>--max-links</option> <replaceable>nrlinks</replaceable></term>
<listitem><para>Keep deleting paths until the hard link count on
<filename>/nix/store</filename> is less than
<replaceable>nrlinks</replaceable>, then stop. This is useful for
very large Nix stores on filesystems with a 32000 subdirectories
limit (like <literal>ext3</literal>).</para></listitem>
</varlistentry>
<varlistentry><term><option>--max-atime</option> <replaceable>atime</replaceable></term>
<listitem><para>Only delete a store path if its last-accessed time
is less than <replaceable>atime</replaceable>. This allows you to
garbage-collect only packages that havent been used recently.
The time is expressed as the number of seconds in the Unix epoch,
i.e., since 1970-01-01 00:00:00 UTC. An easy way to convert to
this format is <literal>date +%s -d "<replaceable>date
specification</replaceable>"</literal>.</para>
<para>For directories, the last-accessed time is the highest
last-accessed time of any regular file in the directory (or in any
of its subdirectories). That is, the <literal>atime</literal>
field maintained by the filesystem is ignored for directories.
This is because operations such as rebuilding the
<command>locate</command> database tend to update the
<literal>atime</literal> values of all directories, so theyre not
a useful indicator of whether a package was recently used.</para>
<para>Note that <command>nix-store --optimise</command> reads all
regular files in the Nix store, and so causes all last-accessed
times to be set to the present time. This makes
<option>--max-atime</option> ineffective (for a while at
least).</para></listitem>
</varlistentry>
<varlistentry><term><option>--use-atime</option></term>
<listitem><para>Delete store paths in order of ascending
last-accessed time. This is useful in conjunction with the other
options to delete only the least recently used
packages.</para></listitem>
</varlistentry>
</variablelist>
</para>
<para>The behaviour of the collector is also influenced by the <link
linkend="conf-gc-keep-outputs"><literal>gc-keep-outputs</literal></link> linkend="conf-gc-keep-outputs"><literal>gc-keep-outputs</literal></link>
and <link and <link
linkend="conf-gc-keep-derivations"><literal>gc-keep-derivations</literal></link> linkend="conf-gc-keep-derivations"><literal>gc-keep-derivations</literal></link>
@ -284,6 +357,20 @@ deleting `/nix/store/kq82idx6g0nyzsp2s14gfsc38npai7lf-cairo-1.0.4.tar.gz.drv'
</para> </para>
<para>To delete unreachable paths not accessed in the last two months:
<screen>
$ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen>
</para>
<para>To delete at least 100 MiBs of unreachable paths:
<screen>
$ nix-store --gc --max-freed $((100 * 1024 * 1024))</screen>
</para>
</refsection> </refsection>
@ -950,7 +1037,51 @@ ktorrent-2.2.1/NEWS
</refsection> </refsection>
<!-- TODO: export, import operations --> <!--######################################################################-->
<refsection><title>Operation <option>--dump-db</option></title>
<refsection>
<title>Synopsis</title>
<cmdsynopsis>
<command>nix-store</command>
<arg choice='plain'><option>--dump-db</option></arg>
</cmdsynopsis>
</refsection>
<refsection><title>Description</title>
<para>The operation <option>--dump-db</option> writes a dump of the
Nix database to standard output. It can be loaded into an empty Nix
store using <option>--load-db</option>. This is useful for making
backups and when migrating to different database schemas.</para>
</refsection>
</refsection>
<!--######################################################################-->
<refsection><title>Operation <option>--dump-db</option></title>
<refsection>
<title>Synopsis</title>
<cmdsynopsis>
<command>nix-store</command>
<arg choice='plain'><option>--load-db</option></arg>
</cmdsynopsis>
</refsection>
<refsection><title>Description</title>
<para>The operation <option>--load-db</option> reads a dump of the Nix
database created by <option>--dump-db</option> from standard input and
loads it into the Nix database.</para>
</refsection>
</refsection>
</refentry> </refentry>

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@ -68,7 +68,7 @@ $ rm __db* log.* derivers references referrers reserved validpaths DB_CONFIG</sc
have been deleted. The option <option>--max-links have been deleted. The option <option>--max-links
<replaceable>N</replaceable></option> tells it to stop after the <replaceable>N</replaceable></option> tells it to stop after the
link count on <filename>/nix/store</filename> has dropped below link count on <filename>/nix/store</filename> has dropped below
<replaceable>N</replaceable>. This is useful on very large Nix <replaceable>N</replaceable>. This is useful for very large Nix
stores on filesystems with a 32000 subdirectories limit (like stores on filesystems with a 32000 subdirectories limit (like
<literal>ext3</literal>). The option <option>--use-atime</option> <literal>ext3</literal>). The option <option>--use-atime</option>
causes store paths to be deleted in order of ascending last access causes store paths to be deleted in order of ascending last access