High Performance WordPress

Gareth Davies

Why performance?

•Speed

•so people don’t wait

•Scale

•serve as many requests to as many people as possible, concurrently

LAMP

•A stack

•LAMP

•Linux

•Apache

•MySQL

•PHP

WordPress

•Written in PHP

•Uses MySQL as the database

•Apache/nginx can be used for HTTP

WordPress

•Core (installed)

•Themes

•Plugins

OS Level Tuning

•You’re 64-bit by now

•Log errors, and nothing else

•TCP/IP settings

•Only run services that you need on a server

OS Level Tuning

•Simple firewall to stop bots

•Read log files from logwatch -- hardware dies too

•vmem.sh

•Filesystem - XFS is best, EXT3, EXT4 are OK too

Apache

•Tune Apache (httpd.conf)

•ab & httperf

•MaxClients

•Defaults are usually horrible

MySQL•Defaults are terrible, use my.cnf

•mysqltuner.pl, tuningprimer.sh

•mytop

•Use maatkit + mk-query-digest

• See general & slow query log (for your plugin problems)

• InnoDB is better for concurrency, though by default you’re probably using MyISAM

•mysqlslap for benchmarking

PHP

•Memory settings

•Opcode cache

•XCache, EAccelerator, APC

•php.ini

WordPress

•Plugins are often horribly coded

•Themes can have direct calls to the database

WordPress

•Look at wp_options tables

•Disable plugins

•Try the new Twenty Ten theme

•wp_config.php: WP_HOME, WP_SITEURL

Still struggling?

•Content Delivery Networks (CDN)

•Minify

•Caching

WP Caches

•WP Super Cache

•W3 Total Cache

More you can do

•use mod_proxy and serve static content

•CDN: Amazon S3+CloudFront is affordable

•use browser cache (set long expires)

Separate machines

•2 machines

•web server

•database server

•memcached servers?

Varnish

•Varnish serves everything from memory

•httpd on a different port, run varnish on port 80 and point it to httpd port

Further growth

•Its now time to think about MySQL replication (master-slave setups)

•memcached to keep caches of query results (up to 1M) in memory

•HyperDB supports data partitioning, and can read from multiple databases

WordPress.COM

•several billion HTTP queries per day, billions of MySQL queries too

•HP hardware, all SSD

HipHop from Facebook

•http://huichen.org/en/2010/06/wordpress-3-benchmark/

•http://huichen.org/en/2010/06/wordpress-3-benchmark-part-2/

•~2.7x improvement in performance

Find Me

•@ShaolinTiger on Twitter

•http://www.shaolintiger.com – My Blog

•shaolintiger at gmail – Email me