Designing Enterprise Drupal

How to scale Drupal server infrastructureENVIRONMENTS

INTRODUCTIONS

• Jason Burnett (jason@neospire.net) NeoSpire Director of Network Services

• Ben Chavet (bchavet@neospire.net)NeoSpire Senior Engineer

• Brian Skowron (bskowron@neospire.net)NeoSpire Account Executive

SO…FIRST THING’S FIRST

• Prerequisites that you’ll need (or at least want).– A good, reliable network with plenty of capacity– At least one expert Systems Administrator

• You don’t necessarily need this:

BUT YOU DON’T WANT THIS:

(hopefully this isn’t you)

AFTER YOU’VE FIRED THAT GUY,

Default Stack Performance Stack

LET’S TALK STACKS

FIRST, DON’T USE DRUPAL (WELL, SORTA)

• Drop-in replacement for Drupal 6.x• Support for database replication• Support for reverse proxy caching• Optimization for MySQL• Optimization for PHP 5 • Available at: http://fourkitchens.com/pressflow-makes-drupal-scale

AFTER PRESSFLOW, IT’S ALL ABOUT CACHE

• Varnish is a reverse proxy cache•Caches content based on HTTP headers• Uses kernel-based virtual memory•Watch out for cookies, authenticated users• Available at http://varnish-cache.org/

HTTP PIPELINEApache Configuration Varnish Configuration

NameVirtualHost *:8080Listen 8080

<VirtualHost *:8080>[…]</VirtualHost>

backend default { .host = "127.0.0.1"; .port = "8080";}

HTTP LOGGING• VarnishNCSA daemon handles logging• Default Apache logs will always show 127.0.0.1• Define a new log format to use X-Forwarded-For

LogFormat "%{X-Forwarded-For}i %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined_proxy

CustomLog /var/log/apache2/access.log combined_proxy

CACHING WITH COOKIESsub vcl_recv { // Remove has_js and Google Analytics __* cookies. set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__[a-z]+|has_js)=[^;]*", "");

// Remove a ";" prefix, if present. set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", "");

// Remove empty cookies. if (req.http.Cookie ~ "^\s*$") { unset req.http.Cookie; }}

sub vcl_hash { // Include cookie in cache hash if (req.http.Cookie) { set req.hash += req.http.Cookie; }}

BASIC SECURITY// Define the internal network subnetsacl internal { "127.0.0.0"/8; "10.0.0.0"/8;}

sub vcl_recv {

[…]

// Do not allow outside access to cron.php if (req.url ~ "^/cron\.php(\?.*)?$" && !client.ip ~ internal) { set req.url = "/404-cron.php"; }}

VARNISH IS SUPER-FAST

/etc/security/limits.conf

• Able to handle many more connections than Apache• Needs a large number of file handles

* soft nofile 131072* hard nofile 131072

APACHE OPTIMIZATIONS

• Tune apache to match your hardware• Setting MaxClients too high is

asking for trouble• Every application is different• A good starting point is total

amount of memory allocated to Apache divided by 40MB• One of the areas that will

need to be monitored and updated on an ongoing basis

STILL ALL ABOUT CACHE• APC Opcode Cache

• APC is an Opcode cache• Officially supported by PHP• Prevents unnecessary PHP

parsing and compiling• Reduces load on Memory

and CPU

ALLOCATE ENOUGH MEMORY

extension=apc.soapc.shm_size=120apc.ttl=300

kernel.shmmax=134217728

Php.ini Sysctl.conf

FOR APC