document tarantar

doc/user/server-administration.xml

@@ -21,9 +21,67 @@
   control flow never reaches the event loop (thanks to a runaway stored
   procedure), the server stops responding to any signal, and
   can be only killed with SIGKILL (this signal can not be ignored).
+</para>
+</section>
+
+<section xml:id="tarantar">
+<title>Utility <code>tarantar</code></title>
+<para>
+The tarantar utility program will create new snapshots by reading existing
+snapshots and write-ahead-log (xlog) files. Thus it differs from <olink targetptr="save-snapshot"/>,
+which creates new snapshots from the database. Since tarantar uses less
+memory than SAVE SNAPSHOT, it is especially appropriate for taking periodic
+snapshots as a background task.
+</para>
+<para>
+To prepare: ensure that the configuration file contains 
+<olink targetptr="wal_dir"/> and <olink targetptr="snap_dir"/>
+clauses. Tarantar does not assume that wal_dir and snap_dir have default values.
+</para>
+<para>
+To run:<programlisting> <command>tarantar</command> [options] <replaceable>configuration-file</replaceable></programlisting>
+where possible options are:<simplelist> <member><code>-i <replaceable>seconds-count</replaceable></code> or <code>--interval <replaceable>seconds-count</replaceable></code> &mdash; repeat every seconds-count seconds. example: <code>-i 3600</code></member>
+ <member><code>-n <replaceable>lsn-number</replaceable></code> or <code>--lsn <replaceable>lsn-number</replaceable></code> &mdash; start from lsn = lsn-number. if not specified, lsn = latest. example: <code>-n 5</code></member>
+ <member><code>-l <replaceable>bytes-count</replaceable></code> or <code>--limit <replaceable>bytes-count</replaceable></code> &mdash; do not use more than bytes-count bytes of memory. example: <code>-l 5000000</code></member>
+ <member><code>--help </code> &mdash; display a help message and exit. example: <code>--help</code></member>
+ <member><code>-v </code> or <code>--version</code> &mdash; display version and exit. example: <code>-v</code></member></simplelist></para>
+<para>
+Example:
+<programlisting>
+<prompt>$ </prompt>~/tarantool/client/tarantar/tarantar -c -i 30 ./tarantool.cfg
+snap_dir: /home/user/tarantool_test/work_dir
+wal_dir:  /home/user/tarantool_test/work_dir
+spaces:   1
+interval: 30
+memory_limit: 0M
+
+START SNAPSHOTTING Fri Oct 25 09:35:25 2013
+
+last snapshot lsn: 7
+(snapshot) 00000000000000000007.snap 0.000M processed
 
+( &gt;&gt; ) 00000000000000000006.snap 0.000M processed
+
+START SNAPSHOTTING Fri Oct 25 09:35:55 2013
+
+last snapshot lsn: 7
+(snapshot) 00000000000000000007.snap 0.000M processed
+
+( &gt;&gt; ) 00000000000000000006.snap 0.000M processed
+
+snapshot exists, skip.
+
+...
+
+</programlisting>
 </para>
+
+<para>
+For an explanation of tarantar's design see <link xlink:href="https://github.com/tarantool/tarantool/wiki/Tarantar">the Tarantool wiki</link>.
+</para>
+
 </section>
+
 <section xml:id="os-install-notes">
 <title>System-specific administration notes</title>
 <blockquote><para>