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Make WordPress Fly with Virtual Server Hosting

Vladimir Lasky

http://wpexpert.com.au/

WordCamp Sydney 2014

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Is This For Me?

Sick of waiting for WP admin pages and edit screens to load

in your browser?

Tired of wrangling with page caches, object caches and

minifying plugins?

Running a database-intensive WordPress site, e.g. e-

commerce site?

Prepared to roll up your sleeves to get a better experience?

Brave enough to forego the “walled garden” of a cPanel in

exchange for true freedom and flexibility?

Then YES!

Shared Web Hosting

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How Shared Web Hosting Limits You

Throttling of Resources

– Network bandwidth

– Running Processes

– Disk I/O

Limited ability to tune & reconfigure services

No PHP Opcode caching

Might have MySQL query caching enabled, but

likely overcommitted

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Why Caching Plugins Are Not The Answer - 1

Two main categories of caching plugins:

– Page caching (e.g. WP Super Cache, Hyper Cache)

– Object Caching

These have cache invalidation overhead/delays

– When the underlying data changes, caches must be

explicitly purged or one must wait for expiry.

– Purging, rebuilding caches causes performance hit –

especially if the cached data is stored on disk

– Stale caches cause non-current information to be

displayed

– Frequently cause issues with plugins/dynamic pages

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Why Caching Plugins Are Not The Answer - 2

They provide no help in speeding up the backend

(WordPress Admin) and usually do nothing for

users who are logged in.

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What About Cloudflare?

A very popular Reverse-Proxy/CDN service

Some useful features, but you are dependent on

them

Have a “free” plan, but no guarantee it will stay

free

CDN based on object pull, so can have cache

invalidation issues

Doesn’t speed up backend (WordPress Admin)

More comments on CDNs later

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What About Minifying Plugins?

These aggregate your site’s CSS and JS files and

compress them by removing white space, new

lines comments and block delimiters.

Examples:

– Better WordPress Minify

– Autoptimize

Somewhat reduce the total requests required to

load your site and the amount of data transferred

Good in theory, but in practice often break things

and require much tweaking to work right

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Why Host WordPress on a VPS?

You can use PHP Opcode Caches, MySQL

Query Caches and other performance enhancers

that don’t have these issues

You have the full ability to customise and tune

services for performance

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What is a VPS?

A Virtual Private Server (VPS) is your very own virtual machine

(VM) running in a datacentre.

The physical server or Virtual Server Host, will be running

multiple VMs simultaneously – yours and other clients of your

hosting provider, but only yours is visible to you.

Cost depends on desired specs – e.g. RAM, disk space, CPUs,

monthly data traffic

Start from as little as $5/month, but can be hundreds for

something hefty

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How Do You Administer a VPS?

A Linux VPS is generally accessed via SSH

A Windows VPS is generally accessed via RDP

Usually there is a facility to view and control the virtual

console, e.g. if the VM hangs and needs to be reset or

reimaged.

You can install and run anything you want (subject to

provider’s Acceptable Use Policy)

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Common Virtual Private Server Types

OpenVZ

– Based on containerization

– Efficient, but does not allow users to change OS kernel

version or have dedicated swap space

– Usually offered at lower price

Xen

– Full ability to customise all aspects of VM configuration

– Allows dedicated swap space

– Some performance overhead

– Usually more expensive

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Why Hosting Control Panels Are Evil

Take over your system – very hard to get rid of or

change

Commercial ones cost money, e.g. $150/yr for

cPanel

Free ones could be abandoned at any time. Risk

of security holes.

Are rather inflexible – you have to wait for

updates to support/take advantage of new

features in other packages

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The Plan

Host WordPress on a Pure SSD VPS with CentOS 6.5

x64. Dual CPUs and 2GB RAM is nice.

Install a PHP Opcode Cache and allocate 120MB RAM

– Choose Zend Optimizer if using PHP 5.5 w/single WordPress

installation

– If Multiple Sites or Older PHP, then XCache

In MySQL config file, enable the Query Cache and

allocate 32MB RAM. Make the key buffer/buffer pool

Configure Apache to launch PHP-FPM in FastCGI mode

and communicate using Unix Sockets

Configure WordPress to access MySQL using Unix

Sockets

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Our Performance-Enhanced Configuration

Common Shared Hosting Configuration

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Differences from a Default Installation

PHP operates as a standalone service (PHP-

FPM) instead of as an Apache module (mod_php)

Apache communicates with PHP-FPM using Unix

Sockets instead of TCP sockets

A PHP Opcode Cache is installed

The MySQL Query cache is enabled

WordPress DB_HOST in wp-config.php is set to

‘localhost’

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Benefits of Our Approach

Not radically different from a default install

Excellent “bang for buck”

No cache invalidation problems

No plugin incompatibilities

Everyone sees the most current state of your site

Logged in users and people working in the

backend will enjoy a speed increase

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Why CentOS?

Free Linux distribution 100% compatible with

Redhat Enterprise Linux – popular Linux

distribution designed for servers

Offered by the vast majority of hosting providers

Security patches are released speedily

Experts are abundant

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Why Unix Sockets?

Less overhead – avoids all network layers below

transport

Lessens risk of ephemeral port exhaustion if site

is bombarded with requests (it does happen)

More secure – they only accept connections from

localhost

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Why Pure SSD VPS Hosting?

HDDs respond to random I/O like busy elevator in

office block – big slowdown when lots of random

requests

SSDs like elevator that teleports to any floor –

cope far better with high, random I/O loads

All server files and databases stored on Solid

State Drives

Greatly improves efficiency, performance of

Shared and Virtual Server Hosting

Beware of “SSD-cached” storage – not as good

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Who Provides Pure SSD Virtual Server Hosting?

Hosted Abroad: – Linode

– DigitalOcean

Hosted in Australia: – Exigent

– Crucial

– ServerMule

– VPSBlocks

More companies are introducing Pure SSD solutions

Australian Pure SSD VPS hosts more expensive and offer

lower data limits, but “there’s no place like home”.

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PHP Opcode Caches - I

The only way to truly make WordPress run faster

WordPress is a PHP program

When PHP code is first executed, it is compiled

into bytecode and stored in shared memory

Future requests will avoid parsing and disk I/O

overhead

120MB is rough yardstick

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PHP Opcode Caches - II

Zend Opcache

– Bundled with PHP 5.5

XCache

– Not as fast as Zend Opcache

+ Recognises identical copies of PHP files

+ Saves lots of RAM if you have multiple WordPress sites

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MySQL Query Cache

WordPress and plugins sends many identical

SQL queries to the server each time a page loads

MySQL can be configured to cache the results,

avoiding the need to parse and execute the query

The Query Cache is automatically invalidated

whenever the database is updated

Transparent to WordPress and plugins

32-64MB is a useful size

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Avoiding CDN Hassles

If you use a CDN for your images, videos or other

assets, ensure that it is configured to operate in

“Origin Push” mode

This means that WordPress will upload content to

the CDN whenever it is added or updated

This avoids cache invalidation issues

W3 Total Cache plugin supports Origin Push CDN

integration for several CDNs, e.g. Amazon,

MaxCDN

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Anything Else To Speed Things Up?

Enable the Apache module mod_deflate to

compress HTML, text, CSS and JavaScript

source files before they are sent to the client.

This speeds up site loading and reduces the

amount of data transferred.

This will work on your current shared host as well!

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Virtual Server Security Tips - 1

Long 20-character true random passwords (use

KeePass to generate and store them)

Regularly apply CentOS software/security updates

– Single command: “yum update -y”

Configure firewall using iptables, to only permit traffic

from authorised ports

Install Fail2ban, bfd or similar brute-force attack

prevention system

Appropriate WordPress Security measures (refer to

previous presentations)

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Virtual Server Security Tips - 2

Be able to “abandon ship” - keep DNS/Email on

separate server, so you can relocate if your server is

ever compromised (p0wned)

Reminder - only UNIX domain sockets for comms

between Apache <-> PHP-FPM and WordPress <->

MySQL

Perform file transfer to/from server using SCP

(operates over SSH)

Alternatively, install Pure-FTPD w/SSL to support

FTPS

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Too Much Hassle! Is There An Easier Way?

Get someone else to set it up and/or do periodic

maintenance

Many Virtual Host providers offer a Virtual Server

management service for an extra monthly fee

You can also contact SAGE-AU - Australia’s peak

body for System Administration Professionals.

They can help you find a local Aussie for casual

SysAdmin work:

– https://www.sage-au.org.au/contact-us

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Conclusion

Additional Tips & Configuration Notes:

– http://wpexpert.com.au/wordcamp-sydney-2014

– Will have configuration examples for PHP-FPM, Apache and MySQL

Questions and Comments:

– http://wpexpert.com.au/contact-us/