</sect2>
</sect1>
+ <sect1 id="lmdbbackend"><title>LMDB (high performance) backend</title>
+ <para>
+ <table>
+ <title>LMDB backend capabilities</title>
+ <tgroup cols="2">
+ <tbody>
+ <row><entry>Native</entry><entry>Yes</entry></row>
+ <row><entry>Master</entry><entry>No</entry></row>
+ <row><entry>Slave</entry><entry>No</entry></row>
+ <row><entry>Superslave</entry><entry>No</entry></row>
+ <row><entry>Autoserial</entry><entry>No</entry></row>
+ <row><entry>DNSSEC</entry><entry>No</entry></row>
+ <row><entry>Module name</entry><entry>lmdb</entry></row>
+ <row><entry>Launch</entry><entry>lmdb</entry></row>
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+ <para>
+ Based on the <ulink url="http://symas.com/mdb/">LMDB key-value
+ database</ulink>, the LMDB backend turns powerdns into a very high
+ performance and DDOS-resilient authoritative DNS server. Testing on a
+ 32-core server shows the ability to answer up to 400,000 queries per second
+ with instant startup and real-time updates independent of database size.
+ </para>
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term>lmdb-datapath=</term>
+ <listitem>
+ <para>
+ Location of the database to load
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <sect2>
+ <title>Operation</title>
+ <para>
+ Unlike other backends LMDB does not require any special configuration.
+ New or updated zones are available the next query after the update
+ transaction is committed. If the underlying database is removed or
+ recreated then the reload command should be sent through to powerdns to
+ get it to close and reopen the database.
+ </para>
+ </sect2>
+ <sect2><title>Database Format</title>
+ <para>
+ A full example script for generating a database can be found in
+ pdns/modules/lmdbbackend/lmdb-example.pl. Basically the database
+ environment is comprised of three databases to store the data:
+ </para>
+ <sect3><title>zone database</title>
+ <para>
+ Each key in the zone database is the reversed lower-cased name of
+ the zone without
+ leading or trailing dots (ie for example.com the key would be moc.elpmaxe).
+ </para>
+ <para>
+ Each value in the database must contain the following data (tab-separated):
+ <variablelist>
+ <varlistentry>
+ <term>Zone ID</term>
+ <listitem>
+ <para>The Zone's unique integer ID in ASCII (32-bit)</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>TTL</term>
+ <listitem>
+ <para>The TTL for the zone's SOA record</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>SOA data</term>
+ <listitem>
+ <para>space-separated SOA data eg
+ <screen>
+ ns.foo.com. hostmaster.foo.com. <serial> <refresh> <retry> <expire> <minimum>
+ </screen>
+ If refresh, retry, expire or minimum are not specified then the powerdns defaults will be used
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </sect3>
+ <sect3 id="lmdb-data"><title>data database</title>
+ <para>
+ This database is required to have been created with the MDB_DUPSORT flag enabled. It stores the records for each domain.
+ Each key must contain the following data (tab-separated):
+ <variablelist>
+ <varlistentry>
+ <term>Record name</term>
+ <listitem>
+ <para>The reversed lower-cased name of the record and zone without leading or trailing dots</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Record type</term>
+ <listitem>
+ <para>The type of record A, NS, PTR etc. SOA is not allowed as it is automatically created from the zone database records.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <para>
+ The value for each entry must contain the following data
+ (tab-separated). If the length of this record is greater than the
+ LMDB limit of 510 bytes (for DUPSORT databases) an entry of "REF"
+ followed by the tab character and a unique 32-bit ASCII integer
+ which contains a reference into <xref linkend="lmdb-extended-data" />.
+ <variablelist>
+ <varlistentry>
+ <term>Zone ID</term>
+ <listitem>
+ <para>The Zone's unique integer ID in ASCII (32-bit)</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>TTL</term>
+ <listitem>
+ <para>The TTL for the SOA record</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Record data</term>
+ <listitem>
+ <para>
+ The record's data entry. For MX/SRV records the
+ priority is the first field and space-separated from the rest
+ of the data. Care must be taken to escape the data
+ appropriately for PowerDNS. As in the Pipe backend " and \
+ characters are not allowed and any it is advised that any
+ characters outside of ASCII 32-126 are escaped using the \
+ character.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </sect3>
+ <sect3 id="lmdb-extended-data"><title>extended_data database</title>
+ <para>
+ If the length of the value that you wish to insert into <xref
+ linkend="lmdb-data" /> is longer than 510 bytes you need to create the
+ REF entry as described above linked in to this table. The value is a
+ unique 32-bit integer value formatted in ASCII and the value is the
+ exact same format as it would have been in <xref linkend="lmdb-data" />
+ but can be however long you require.
+ </para>
+ </sect3>
+
+ <sect3><title>Example database structure</title>
+ <para>
+ (as output by the pdns/modules/lmdbbackend/lmdb-example.pl example script and shown by pdns/modules/lmdbbackend/dumpdb.pl)
+ <screen>
+ # perl dumpdb.pl /var/tmp/lmdb zone
+ key: moc.elpmaxe; value: 1 300 ns.example.com. hostmaster.example.com. 2012021101 86400 7200 604800 86400
+ # perl dumpdb.pl /var/tmp/lmdb data
+ key: moc.elpmaxe MX; value: 1 300 10 mail.hotmail.com
+ key: moc.elpmaxe NS; value: 1 300 ns.example.com
+ key: moc.elpmaxe.tset A; value: 1 300 1.2.3.4
+ key: moc.elpmaxe.txet TXT; value: 1 300 test\010123
+ key: moc.elpmaxe.txetgnol TXT; value: REF 1
+ # perl dumpdb.pl /var/tmp/lmdb extended_data
+ key: 1; value: 1 300 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+ </screen>
+ </para>
+ </sect3>
+ </sect2>
+ </sect1>
+
<sect1 id="odbc">
<title>ODBC backend</title>
<para>
projects / thirdparty / pdns.git / blobdiff