BIND + DLZ と PowerDNS のパフォーマンス比較
とある IRC チャネルで DNS ソフトウェアの話になって、当然 BIND や djbdns があがってくるわけなんですが、うち PowerDNS つかってて、ベンチマークとった資料とかあるよ、と言ったら、あんま事例ないと思うのでブログで公開するとうれしい人が多いかも、と Ficia を アツく語る人 から言われたので公開します。2年ちょいぐらい前につくった資料で、細かいこと忘れちゃってますし、社内向けに書いたものを公開するので、マズいところは省いたりしてます。
まずは VM 環境で、BIND + DLZ と PowerDNS（どちらもバックエンドに MySQL を使用）のパフォーマンス比較した資料を公開します。
BIND + DLZ のパフォーマンス
/etc/named.conf
dlz "Mysql zone" {
database "mysql
{host=localhost dbname=dns_data ssl=false}
{select zone from dns_records where zone = '%zone%'}
{select ttl, type, mx_priority, case when lower(type)='txt' then concat('\"', data, '\"')
else data end from dns_records where zone = '%zone%' and host = '%record%'
and not (type = 'SOA' or type = 'NS')}
{select ttl, type, mx_priority, data, resp_person, serial, refresh, retry, expire, minimum
from dns_records where zone = '%zone%' and (type = 'SOA' or type='NS')}
{select ttl, type, host, mx_priority, data, resp_person, serial, refresh, retry, expire,
minimum from dns_records where zone = '%zone%' and not (type = 'SOA' or type = 'NS')}
{select zone from xfr_table where zone = '%zone%' and client = '%client%'}
{update data_count set count = count + 1 where zone ='%zone%'}";
};
MySQLに登録された DNS レコード
mysql> select * from dns_records; +-------------+------+------+--------------+-------+-------------+---------+-------+---------+---------+----------+-------------------+------------+ | zone | host | type | data | ttl | mx_priority | refresh | retry | expire | minimum | serial | resp_person | primary_ns | +-------------+------+------+--------------+-------+-------------+---------+-------+---------+---------+----------+-------------------+------------+ | example.org | @ | SOA | localhost. | 86400 | 10 | 3600 | 200 | 3600000 | 3600 | 20070919 | test.example.org. | NULL | | example.org | www | A | 192.168.32.1 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | example.org | abc | A | 192.168.32.2 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | example.org | test | A | 192.168.32.3 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | +-------------+------+------+--------------+-------+-------------+---------+-------+---------+---------+----------+-------------------+------------+
dns_records テーブルのインデックスの状態
mysql> show index from dns_records; +-------------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +-------------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | dns_records | 1 | host_index | 1 | host | A | NULL | 20 | NULL | YES | BTREE | | | dns_records | 1 | zone_index | 1 | zone | A | NULL | 30 | NULL | YES | BTREE | | | dns_records | 1 | type_index | 1 | type | A | NULL | 8 | NULL | YES | BTREE | | +-------------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
queryperf 用ファイル
test.example.org A
queryperf の実行結果
# queryperf -d ~/dlz_test.dat -s 127.0.0.1 -l 10 DNS Query Performance Testing Tool Version: $Id: queryperf.c,v 1.8.192.3 2005/10/29 00:21:12 jinmei Exp $ [Status] Processing input data [Status] Sending queries (beginning with 127.0.0.1) [Status] Testing complete Statistics: Parse input file: multiple times Run time limit: 10 seconds Ran through file: 974 times Queries sent: 975 queries Queries completed: 975 queries Queries lost: 0 queries Queries delayed(?): 0 queries RTT max: 2.775003 sec RTT min: 0.043778 sec RTT average: 0.253777 sec RTT std deviation: 0.335064 sec RTT out of range: 0 queries Percentage completed: 100.00% Percentage lost: 0.00% Started at: Thu Sep 20 19:38:22 2007 Finished at: Thu Sep 20 19:38:35 2007 Ran for: 12.619786 seconds Queries per second: 77.259630 qps
PowerDNS のパフォーマンス
MySQL に登録された DNS レコード
mysql> select * from records; +----+-----------+--------------------+------+-------------------------+-------+------+-------------+ | id | domain_id | name | type | content | ttl | prio | change_date | +----+-----------+--------------------+------+-------------------------+-------+------+-------------+ | 1 | 1 | test.com | SOA | localhost ahu@ds9a.nl 1 | 86400 | NULL | NULL | | 2 | 1 | test.com | NS | dns-us1.powerdns.net | 86400 | NULL | NULL | | 3 | 1 | test.com | NS | dns-eu1.powerdns.net | 86400 | NULL | NULL | | 4 | 1 | www.test.com | A | 199.198.197.196 | 120 | NULL | NULL | | 5 | 1 | mail.test.com | A | 195.194.193.192 | 120 | NULL | NULL | | 6 | 1 | localhost.test.com | A | 127.0.0.1 | 120 | NULL | NULL | | 7 | 1 | test.com | MX | mail.test.com | 120 | 25 | NULL | +----+-----------+--------------------+------+-------------------------+-------+------+-------------+
records テーブルのインデックスの状態
mysql> show index from records; +---------+------------+----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +---------+------------+----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | records | 0 | PRIMARY | 1 | id | A | 7 | NULL | NULL | | BTREE | | | records | 1 | rec_name_index | 1 | name | A | 7 | NULL | NULL | YES | BTREE | | | records | 1 | nametype_index | 1 | name | A | 7 | NULL | NULL | YES | BTREE | | | records | 1 | nametype_index | 2 | type | A | 7 | NULL | NULL | YES | BTREE | | | records | 1 | domain_id | 1 | domain_id | A | 2 | NULL | NULL | YES | BTREE | | +---------+------------+----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
queryperf 用設定ファイルの内容
www.test.com A
queryperf の実行結果
# queryperf -d ~/pdns_test.dat -s 127.0.0.1 -l 10 DNS Query Performance Testing Tool Version: $Id: queryperf.c,v 1.8.192.3 2005/10/29 00:21:12 jinmei Exp $ [Status] Processing input data [Status] Sending queries (beginning with 127.0.0.1) [Status] Testing complete Statistics: Parse input file: multiple times Run time limit: 10 seconds Ran through file: 42159 times Queries sent: 42160 queries Queries completed: 42160 queries Queries lost: 0 queries Queries delayed(?): 0 queries RTT max: 0.013259 sec RTT min: 0.000331 sec RTT average: 0.002268 sec RTT std deviation: 0.001248 sec RTT out of range: 0 queries Percentage completed: 100.00% Percentage lost: 0.00% Started at: Thu Sep 20 19:36:47 2007 Finished at: Thu Sep 20 19:36:57 2007 Ran for: 10.000367 seconds Queries per second: 4215.845278 qps
結論
BIND + DLZ: 77.259630 qps、PowerDNS: 4215.845278 qps で PowerDNS の圧勝。これは BIND + DLZ がリクエスト毎に MySQL 問い合わせしてるのに対し、PowerDNS はメモリにキャッシュしていちいち MySQL に問い合わせないから、だろう。
