This page contains some information about deprecated backends.
LMDB (high performance) backend
Note: This backend was removed in version 4.0.0.
Based on the LMDB key-value database, 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.
Location of the database to load
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.
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:
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).
Each value in the database must contain the following data (tab-separated):
- Zone ID: The Zone's unique integer ID in ASCII (32-bit)
- TTL: The TTL for the zone's SOA record
- SOA data: space-separated SOA data eg
ns.foo.com. hostmaster.foo.com. <serial> <refresh> <retry> <expire> <minimum>
If refresh, retry, expire or minimum are not specified then the powerdns defaults will be used
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):
- Record name: The reversed lower-cased name of the record and zone without leading or trailing dots
- Record type: The type of record A, NS, PTR etc. SOA is not allowed as it is automatically created from the zone database records.
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 the section called “extended_data database”.
- Zone ID: The Zone's unique integer ID in ASCII (32-bit)
- TTL: The TTL for the SOA record
- Record data: 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.
If the length of the value that you wish to insert into the section called “data database” 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 the section called “data database” but can be however long you require.
Example database structure
(as output by the pdns/modules/lmdbbackend/lmdb-example.pl example script and shown by pdns/modules/lmdbbackend/dumpdb.pl)
# 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.example.com key: moc.elpmaxe NS; value: 1 300 ns.example.com key: moc.elpmaxe.tset A; value: 1 300 192.0.2.66 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
Note: This backend was removed in version 3.5.0.
PowerDNS is currently ascertaining if this backend can be distributed in binary form without violating IBM DB2 licensing.
The DB2 backend executes the following queries:
select Content, TimeToLive, Priority, Type, ZoneId, 0 as ChangeDate, Name from Records where Name = ? and type = ?
Forward By Zone Query
select Content, TimeToLive, Priority, Type, ZoneId, 0 as ChangeDate, Name from Records where Name = ? and Type = ? and ZoneId = ?
Forward Any Query
select Content, TimeToLive, Priority, Type, ZoneId, 0 as ChangeDate, Name from Records where Name = ?
select Content, TimeToLive, Priority, Type, ZoneId, 0 as ChangeDate, Name from Records where ZoneId = ?
Server name to connect to. Defaults to 'powerdns'. Make sure that your nameserver is not needed to resolve an IP address needed to connect as this might lead
Username to connect as. Defaults to 'powerdns'.
Password to connect with. Defaults to 'powerdns'.
Note: This backend was removed in version 3.1.
The ODBC backend can retrieve zone information from any source that has a ODBC driver available.
Note This backend is only available on PowerDNS for Windows.
The ODBC backend needs data in a fixed schema which is the same as the data needed by the MySQL backend. The create statement will resemble this:
CREATE TABLE records ( id int(11) NOT NULL auto_increment, domain_id int(11) default NULL, name varchar(255) default NULL, type varchar(10) default NULL, content varchar(255) default NULL, ttl int(11) default NULL, prio int(11) default NULL, change_date int(11) default NULL, PRIMARY KEY (id), KEY name_index(name), KEY nametype_index(name,type), KEY domainid_index(domain_id) );
To use the ODBC backend an ODBC source has to be created, to do this see the section Installing PowerDNS on Microsoft Windows, not included in the documentation as installation on Windows is not supported.
Specifies the name of the data source to use.
Specifies the username that has to be used to log into the data source.
Specifies the user's password.
Specifies the name of the table containing the zone information.
The ODBC backend has been tested with Microsoft Access, MySQL (via MyODBC) and Microsoft SQLServer. As the SQL statements used are very basic, it is expected to work with many ODBC drivers.
No longer part of PowerDNS.