High Performance Drupal
Making Your Site Fast Fast Fast

Drupal Is Powerful

Drupal is Slow

Databases are Slow

PHP Is Slow

Consumer-Grade Networks Are
Slow

Increasing Speed Means Diving
Less Deeply Into The Stack

Fast Is Making Fewer Requests
From Faster Sources

The Life Of A Pageload
• Browser Request
• Browser Cache?
• Network Request
• Server Response
• Associated Assets (back to top)

Optimizing For The Browser
• Make Your HTML/CSS Images Efficient
• Use CSS/JS Aggregation
• Use a CDN
• Yslow is good for profiling this

Optimizing Server Response
• Reverse Proxy/Drupal Page Cache
• PHP OpCode Cache
• Drupal System Cache

Reverse-Proxies Are Very Fast

Faster Than Apache

Much Faster Than Drupal

Don’t Bother Your Power Tools
With Simple Tasks

Implementing Varnish
• Use Pressflow
• Implement A Simple VCL Based On Sessions
• Enable Aggressive Caching
• Enjoy, Experiment, Excel

OpCode Caching Keeps Drupal
Loaded In Memory

Don’t Touch The Disk

Don’t Load Up Apache Threads
With Copies of Drupal

Implementing APC
• The Biggest/Cheapest Win
• Install via apt-get, yum, or pecl
• Monitor with apc.php
• Lots of modules? Bump the SHM size
• Enable apc.stat=0 with caution

Drupal Freezes It’s Code Before
Launch

Most Real-World Scaling
Information Comes After Release

Drupal Supports A Crazy Array Of
Use Cases

$5/month Shared Hosting Is Not
High Performance

Pressflow
• “Pressflow Makes Drupal Scale”
• Drop-in Replacement For Core
• Backports many Drupal 7 features
• PHP 5.x/MySQL 5.x Required
• Enables robust reverse-proxy, mysql replication and more
• Runs drupal.org and many other high-performance sites

Drupal Has A Cache And That Is
Good

But... Drupal’s Cache Is In The
Database

And Serialized.

That Works Anywhere, But Is Both
Slow and Expensive

CacheRouter
• Use settings.php to plug in cacherouter instead of /includes/cache.inc
• Pick your poison: APC, XCache, Memcached, Filesystem, or classic db
caching.
• Change caches per table.
• Vital for high-speed logged-in pageloads.

Coming Soon: Advcache
• Cache Nodes, Users, Taxonomy Terms and other common objects via
cacherouter.
• Extends the notion of drupal’s static cache to whole objects.
• Still in development, but if you’re into writing patches...

Other Tips
• Search is among the slowest and most expensive queries. Use Solr
instead.
• InnoDB can help with locking in MySQL
• Hardware is faster and often more cost effective than code cleanup.
• Monitor load and scale ahead of problems.

Benchmarking/Profiling
• Cachegrind to profile code.
• Jmeter to simulate load.
• Slow Query logs, cactai, etc.

Vertical/Horizntal Scaling
• Start with all services you need.
• Separate services into layers.
• Add more servers at each layer as needed.
• Shameless plug: Project Mercury: http://getpantheon.com

More Resources
• http://groups.drupal.org/high-performance
• http://pressflow.org
• http://tag1consulting.com
• http://2bits.com
• http://getpantheon.com