1.
JAMES FULLER
02/13/2013
Simply Scale
w/ Nginx, Memcached, PHP-FPM and APC

2.
In this talk...
● my experiences working in a high-traffic
environment
● intro to nginx for apache users
● running php with php-fpm
● memcached & caching tips
● identifying bottlenecks / open discussion

3.
The Early Years
Cheap Shared Hosting

4.
Into the fire

5.
A Simple Scaling
Architecture
NGINX PHP-FPM
MEMCACHED
PHP-FPM
PHP-FPM
MYSQL MASTER
PHP-FPM
MYSQL SLAVE

6.
Apache
Awesome when you need to assault your server

7.
The classic setup - prefork
MPM w/ mod_php
● prefork is default mode prior to v2.4
● forks (creates) new process per web
resource requested
● runs php via a module (mod_php)

8.
Apache prefork
performance killers
● Loads all modules for each forked process
● Keepalive timeout
● AllowOverride (.htaccess)

9.
Apache 2.4
● Event MPM is now the default MPM in
Apache 2.4
● Event MPM designed to solve the keepalive
problem
● Can talk to PHP-FPM via mod_proxy_fcgi
● Needs thread safe php

10.
Many reasons to keep
Apache
● apache modules
● very mature software
● can tune for good results
● plays nice with nginx!

11.
NGINX
Russian for Fast

12.
What is NGINX?
● HTTP Server
● Reverse Proxy
● IMAP/POP3 proxy server
● Open Source

13.
Who is using nginx?

14.
Nginx performance
advantages
● event based connection handling
● low/predictable memory consumption
● works well in low resource environments
(VPS)
● can handle tens of thousands of concurrent
requests*

15.
Nginx as a frontend
● serve static files
● frontend for apache for php
● no apache, via PHP-FPM
● serve content directly from memcached

16.
Nginx Configuration
user nginx;
worker_processes 1;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
server {
location / {
#do something
}
}
}

17.
a series of blocks
http {
access_log /var/log/nginx/access.log main;
include /etc/nginx/conf.d/*.conf;
gzip on;
server {
server_name myserver.com www.myserver.com
listen 80;
location / {
}
}
}

18.
server blocks
server {
listen 80 default_server;
server_name star.yourdomain.com *.yourdomain.com;
root /PATH/TO/WEBROOT;
error_page 404 errors/404.html;
access_log logs/star.yourdomain.com.access.log;
index index.php index.html index.htm;
}

19.
location blocks
# static file 404's not logged + expires header set to maxage
location ~* .(jpg|jpeg|gif|css|png|js|ico|html)$ {
access_log off;
expires max;
}
# deny htaccess
location ~ /.ht {
deny all;
}

20.
PHP-FPM
it's like mod_php without Apache

21.
PHP-FPM are you
listening?
● included with php as of 5.3.3
● runs as a daemon
○ listens for requests via socket or port
(FastCGI)
● Decouple web server from executing php
code

22.
Talking to php-fpm
# pass the PHP scripts to FastCGI server
# listening on 127.0.0.1:9000
location ~ .php$ {
root html;
fastcgi_pass 127.0.0.1:9000;
#fastcgi_pass unix:/tmp/php.socket
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
include fastcgi_params;
}

23.
Nginx for load balancing
● round robin
● least connections
● ip segmenting
● sticky backends

24.
upstream server
upstream backend {
server backend1.example.com weight=5;
server backend2.example.com:8080;
server unix:/tmp/backend3;
}
server {
location / {
proxy_pass http://backend;
}
}

25.
apache frontend
upstream backend {
server 192.168.1.2;
server 192.168.1.3;
server 192.168.1.4;
#etc
}
location ~ .php$ {
proxy_pass http://backend;
proxy_set_header X-Real-IP $remote_addr;
}

26.
Nginx Modules
Core Log
Access Map OPTIONAL
Addition Secure Link
Auth Basic Memcached
Auto Index Degradation SSL
Proxy
Browser Embedded Perl Stub Status
Referer
Charset FLV Substitution
Rewrite
Empty GIF GeoIP WebDAV
SCGI
FastCGI Google
Split Clients XSLT
Geo Perftools
Gzip SSI Gzip
Headers Upstream Precompression
Index User ID Image Filter
Limit Requests uWSGI MP4
Limit Zone X-Accel Random Index
Limit Conn
Real IP

27.
Caching in PHP
Cache is king

28.
What is Memcached?
● invented by Brad Fitzpatrick to solve
livejournal performance problems
● distributed key value store
● super fast

29.
Set up Memcached
instances
● small sites can use as little as 25MB
● best results and reliability in a cluster

30.
Talking to Memcached with
PHP
● naming disaster
● php has two memcached extensions
○ memcache
○ memcached - better support for advanced
features
○ wtf?
● memcache(d) php extension only on nix
platforms (no windows)

31.
Connecting to Memcached
<?php
$cache = new Memcache;
$cache
->addServer('192.168.1.2', 11211, ..[OPTIONS]..);
$cache
->addServer('192.168.1.3', 11211, ..[OPTIONS]..);
$cache
->addServer('192.168.1.4', 11211, ..[OPTIONS]..);
$cache
->addServer('192.168.1.5', 11211, ..[OPTIONS]..);

32.
Simple Cache strategy
<?php
$key = 'mystash';
$data = $cache->get($key);
if ($data === false) {
$data = 'fill up the data';
$cache->set($key, $data, ..[OPTIONS]..);
}

33.
Be smart about caching
● cache expensive things (network, db)
● stale content can be much worse than slow
content
● have a plan to expire cache entries

34.
APC
● Opcode cache
● Stores ready-to-run machine code
● will eventually be replaced by zend optimizer
(php 5.5)
● has data caching api

35.
Bottlenecks &
Benchmarking
Try to identify bottlenecks

36.
Find out what is slow
● web server
● database
● bandwidth / infrastructure
● php code

37.
Avoid the file system
● does not scale well
● expensive to make fast
● cloud hosting and multi-server
implementations more complicated

38.
Database
● often the culprit
● choose the right technologies
● don't skimp on hardware

39.
Other people's benchmarks
● Monitoring and testing is key
● avoid magical thinking:
○ "Magical thinking is thinking that one's thoughts by themselves can
bring about effects in the world or that thinking something corresponds
with doing it"
● use tools like newrelic with actual users

40.
It's all about the end user
● avoid blocking javascript
● be aware of static assets
● use expires headers correctly

41.
Seriously, try New Relic
● FREE basic account, with PRO TRIAL
● runs as a deamon + php extension
● allows deep inspection of web transactions
● need ability to install package on server

42.
Homework

43.
Dig one level deeper
● We work in abstractions
● Understand the systems that deliver your
code to the browser
● Identify the problems before implementing
the solutions

44.
Resources
● nginx wiki - http://wiki.nginx.org/
● php-fpm - http://php.net/manual/en/install.fpm.php
● memcached - http://memcached.org/
● memcache extensions
○ memcache - http://php.net/manual/en/book.
memcache.php
○ memcache(d) - http://php.net/manual/en/book.
memcached.php
● apc - http://php.net/manual/en/book.apc.php
● newrelic - http://newrelic.com/

45.
Questions?
James Fuller
@j_blotus
http://www.jblotus.com