This chapter introduces you to the multisite feature that s built into the

Chapter 1: An Introduction to Multiple Sites In This Chapter Discovering where multiple sites began Exploring what you can do with multiple sites Configuring your web server This chapter introduces you to the multisite feature that s built into the WordPress software. The multisite feature allows you, the site owner, to add and maintain multiple blogs within a single installation of WordPress. In this chapter, you discover how the multisite feature works and why you might want to use it. You also explore how to configure and set up your web server environment for use with the multisite feature. With the multisite feature enabled, users of your network can run their own sites within your installation of WordPress. They also have access to their own Dashboard with the options and features you read about in the previous minibooks. Heck, it s probably a good idea to buy a copy of this book for the members of your network so they can become familiar with the WordPress Dashboard and features, too. At least have a copy on hand so people can borrow yours! Deciding When to Use the Multisite Feature Usually, for multiple users to post to one site, WordPress is sufficient. The multiuser part of the WordPress MU name didn t refer to how many users were added to your WordPress website, really. MU was always a bit of a misnomer and an inaccurate depiction of what the software actually did. A network of sites is a much closer description. COPYRIGHTED MATERIAL Determining whether to use the multisite feature depends on user access and publishing activity. Each site in the network, although sharing the same codebase and users, is still a self-contained unit. Users still have to access the back end of each site to manage options or post to that site. A limited number of general options are network-wide, and posting is not one of them. You can use multiple sites in a network to give the appearance that only one site exists. Put the same theme on each site, and the visitor doesn t realize that they re separate. This is a good way to separate sections of a magazine

710 Deciding When to Use the Multisite Feature site, using editors for complete sections (sites) but not letting them access other parts of the network or the back end of other sites. Another factor to consider is how comfortable you are with editing files directly on the server. Setting up the network involves accessing the server directly, and ongoing maintenance and support for your users can often lead to the network owner doing the necessary maintenance, which is not for the faint of heart. Generally, you should use a network of sites in the following cases: You want multiple sites and one installation. You re a blogger or site owner who wants to maintain another site, possibly with a subdomain or a separate domain, all on one web host. You re comfortable with editing files, you want to work with one codebase to make site maintenance easier, and most of your plugins and themes are accessible to all the sites. You can have one login across the sites and manage each site individually. You want to host blogs or sites for others. This is a little more involved. You want to set up a network where users can sign up for their own sites or blogs underneath (or part of) your main site and you maintain the technical aspects for them. Because all files are shared, some aspects have been locked down for security purposes. One of the most puzzling security measures for new users is the suppression of errors. Most PHP errors (say you installed a faulty plugin or incorrectly edited a file) don t output messages to the screen. Instead, what appears is what I like to call the White Screen of Death. Knowing how to find and use error logs and do general debugging are necessary skills for managing your own network. Even if your web host will set up the ongoing daily or weekly tasks for you, managing a network can involve a steep learning curve. When you enable the multisite feature, the existing WordPress site becomes the main site in the installation. Although WordPress can be quite powerful, in the following situations the management of multiple sites has its limitations: One web account is used for the installation. You can t use multiple hosting accounts. You want to post to multiple blogs at one time. WordPress doesn t do this by default. If you choose subdirectory sites, the main site will regenerate permalinks with /blog/ in it to prevent collisions with subsites. There are existing plugins available to prevent this regeneration.

Understanding the Difference between Sites and Blogs 711 The best example of a large blog network with millions of blogs and users is the hosted service at WordPress.com (http://wordpress.com). At WordPress.com, people are invited to sign up for an account and start a blog using the multisite feature within the WordPress platform on the WordPress server. When you enable this feature on your own domain and enable the user registration feature, you re inviting users to do the following: Create an account. Create a blog on your WordPress installation (on your domain). Create content by publishing blog posts. Upload media files such as photos, audio, and video. Invite friends to view their blog or to sign up for their own account. Understanding the Difference between Sites and Blogs With the merger of WordPress MU and WordPress came a terminology change. Each additional blog under WordPress MU is now a site instead of a blog. But, what s the difference? Largely, it s one of perception. Everything functions the same, but people can see greater possibilities when they no longer think of each site as just a blog. Now, WordPress can be so much more: With the addition of the Domain Mapping plugin (see Chapter 6 in this minibook), you can manage multiple sites with different, and unique, domain names. None of them has to be a blog. They can have a blog element, or just use pages and have a static site. The built-in options let you choose between subdomains or subfolder sites when you install the network. If you install WordPress in the root of your web space, you get subdomain.yourdomain.com (if you choose subdomains) or yourdomain.com/subfolder (if you choose subfolders). Chapter 2 of this minibook discusses the differences and advantages. After you choose the kind of sites you want to host and then create those sites, you can t change them later on. These sites are served virtually, meaning that they don t exist as files or folders anywhere on the server. They exist only in the database. The correct location is served to the browser by using rewrite rules in the.htaccess file. (See Book II, Chapter 5.) The main, or parent, site of the network can also be a landing page of the entire network of sites, showcasing content from other sites in the network and drawing in visitors further. Book VIII Chapter 1 An Introduction to Multiple Sites

712 Setting Up the Optimal Hosting Environment Setting Up the Optimal Hosting Environment This chapter assumes that you already have the WordPress software installed and running correctly on your web server and that your web server meets the minimum requirements to run WordPress. Before you enable the WordPress multisite feature, you need to determine how you are going to use the feature. You have a couple of options: Manage just a few of your own WordPress blogs or websites. Run a full-blown blogging network with several hundred different blogs and multiple users. If you re planning to run just a few of your own sites with the WordPress multisite feature, then your current hosting situation is probably well suited. However, if your plans are to host a large network with hundreds of blogs and multiple users, you should consider contacting your host and increasing your bandwidth, as well as the disk space limitations on your account. In addition to the necessary security measures, time, and administrative tasks that go into running a community of blogs, you have a few more things to worry about. Creating a community increases the resource use, bandwidth use, and disk space on your web server. In many cases, if you go over the allotted limits given to you by your web host, you will incur hefty costs. Make sure that you anticipate your bandwidth and disk space needs before running a large network on your website! (Don t say I didn t warn you.) Checking out shared versus dedicated hosting Many WordPress network communities start with grand dreams of developing a large and active community. Be realistic about how your community will operate in order to make the right hosting choice for yourself and your community. Small blogging communities can be handled easily by using a shared-server solution, whereas larger, more active communities may require a dedicatedserver solution for operation. The difference between the two lies in their names: Shared-server solution: You have one account on one server that has several other accounts on it. Think of this as apartment living. One apartment building has several apartments for multiple people to live, all under one roof. Dedicated-server solution: You have one account. You have one server. That server is dedicated to your account, and your account is dedicated to the server. Think of this as owning a home where you don t share your living space with anyone else.

Setting Up the Optimal Hosting Environment 713 A dedicated-server solution is a more expensive investment for your blog community, while a shared-server solution is the most economical. Your decision on which solution to use for your network blogging community will be based on your realistic estimates of how big and how active your community will be. You can move from a shared-server solution to a dedicatedserver solution if your community gets larger than you expected; however, starting with the right solution for your community from day one is easier. Exploring subdomains versus subdirectories The WordPress multisite feature gives you two ways to run a network of blogs on your domain. You can use the subdomain option or the subdirectory option. The most popular option (and recommended structure) sets up subdomains for the blogs created within WordPress network of sites. With the subdomain option, the username of the blog appears first, followed by your domain name. With the subdirectory option, your domain name appears first, followed by the username of the blog. Which one should you choose? The choice is yours. You can see the difference in the URLs of these two options by comparing the following examples: A subdomain looks like this: http://username.yourdomain.com A subdirectory looks like this: http://yourdomain.com/username While the network is being set up, tables are added (to the database) that contain information about the network, including the main site URL. If you re developing a site or want to change the domain later, you need to change every reference to the domain name in the database. Look at Book II, Chapter 3 to find more about the WordPress database structure, including how data is stored in tables, as well as the use of a popular database administration tool called phpmyadmin to manage, view, and edit database tables. Choosing Linux, Apache, MySQL, and PHP server environments A network of sites works best on a LAMP (Linux, Apache, MySQL, and PHP) server with the mod_rewrite Apache module enabled. Mod_rewrite is an Apache module that builds URLs that are easier to read. (Also, see the nearby Apache mod_rewrite sidebar for more information.) In WordPress, this Apache module is used for permalinks. If your install uses any permalink other than the default,?p=123, then you re okay. Your web host can help you determine whether your web server allows this. It is a requirement for setting up the WordPress multisite feature. (You can find more information on permalink structure in Book III, Chapter 2.) Book VIII Chapter 1 An Introduction to Multiple Sites For the purposes of this chapter, I stick to the LAMP server setup because it is most similar to the average web host and is most widely used.

714 Setting Up the Optimal Hosting Environment Apache (http://httpd.apache.org) is software that s loaded and running on your web server. Usually, the only person who has access to Apache files is the web server administrator. (This is usually your web host.) Depending on your own web server account and configuration, you may or may not have access to the Apache software files. The Apache module that s necessary in order for the WordPress network to create nice permalink URLs is called mod_rewrite. This must be configured so that it s active and installed on your server. Apache mod_rewrite You or your web host can make sure that the Apache mod_rewrite is activated on your server; open the httpd.conf file and verify that the following line is included within: LoadModule rewrite_module / libexec/mod_rewrite.so If it isn t, type that line on its own line and save the file. You probably need to restart Apache before the change takes effect. Remember that the Apache mod_rewrite module is required for WordPress multisites. If you don t know whether your current hosting environment has this module in place, drop an e-mail to your hosting provider and ask. The provider can answer that question for you (in addition to installing the module for you in the event that your server doesn t yet have it). Networks also work well on Nginx and Lightspeed servers; however, many users have reported having much difficulty on IIS (Windows) servers. Therefore, I don t recommend setting up WordPress with multisite features on a Windows server environment. Subdomain sites work by way of a virtual host entry in Apache, also known as a wildcard subdomain. On shared hosts, your web hosting provider support team will have to enable this for you, or they may already have done so for all accounts. It is best to ask your hosting provider before you begin. In these situations, the domain you use for your install must be the default domain in your account. Otherwise, the URLs of your subsites will fail to work properly or to have a folder name in the URL. Some hosts may require you to have a dedicated IP address, but this isn t a specific software requirement for a WordPress network to function. Before proceeding with the final steps in enabling the WordPress multisite feature, you need to get a few items in order on your web server. You also need to make a decision about how the multiple blogs within your network will be handled. These configurations need to be in place in order to run the WordPress network successfully.

Setting Up the Optimal Hosting Environment 715 Adding a virtual host to the Apache configuration You need to add a hostname record pointing at your web server in the DNS configuration tool available in your web server administration software, such as WebHost Manager (WHM), a popular web host administration tool. In this section, you edit and configure Apache server files. If you can perform the configurations in this section yourself (and if you have access to the Apache configuration files), this section is for you. If you don t know how, are uncomfortable with adjusting these settings, or don t have access to change the configurations in your web server software, you need to ask your hosting provider for help or hire a consultant to perform the configurations for you. I can t stress enough that you shouldn t edit the Apache server files yourself if you aren t comfortable with it or don t fully understand what you re doing. Web hosting providers have support staff to help you with these things if you need it take advantage of that! The hostname record looks like this: *.yourdomain.com (where your domain.com is replaced with your actual domain name). Follow these steps to enable the wildcard subdomains in Apache: 1. Log in as the root user to your server. 2. Open the httpd.conf file or the vhost include file for your current web account. 3. Find the virtual host section for your domain. 4. Add the wildcard subdomain record next to the domain name. It will look like this: ServerAlias yourdomain.com *.yourdomain.com 5. Save the file. 6. Restart Apache. You also need to add a wildcard subdomain DNS record. Depending on how your domain is set up, you can do this at your registrar or your web host. If you simply pointed to your web host s nameservers, then you can add more DNS records at your web host in the web server administration interface, such as WHM (Web Host Manager). You also should add a CNAME record with a value of *. CNAME stands for Canonical Name and is a record stored in the DNS settings of your Apache web server that tells Apache you would like to associate a new subdomain with the main account domain. Applying the value of * tells Apache to send any subdomain requests to your main domain, and from there, WordPress looks up that subdomain in the database to see whether it exists. Book VIII Chapter 1 An Introduction to Multiple Sites

716 Setting Up the Optimal Hosting Environment Networks require a great deal more server memory (RAM) than typical WordPress sites (not using the multisite feature), simply because multisites are generally bigger, have a lot more traffic, and use up more database space and resources because multiple sites are running (as opposed to just one with regular WordPress). You aren t simply adding instances of WordPress. You re multiplying the processing and resource use of the server when you run the WordPress multisite feature. Although smaller instances of a network run okay on most web hosts, you may find that when your network grows, you need more memory. I generally recommend that you start with a hosting account that has access to at least 256MB of RAM (memory). For each site created, nine additional tables are added to the single database. Each table has a prefix similar to wp_blog-id_tablename (where BLOG-ID is a unique ID assigned to the site). The only exception to this is the main site. Its tables remain untouched, and remain the same. (See Book II, Chapter 3 to see how its tables look.) With WordPress multisites, all new installations leave the main blog tables untouched and number additional site tables sequentially, with every new site that is added to the network. Much discussion about the database layout has occurred in Trac, the WordPress codebase management system, and in the WordPress.org forums. Although Trac may seem unwieldy, it scales appropriately. Limitations on database size have more to do with the server and database management tools. The average users build a small to medium-sized network, which usually needs no more than a VPS (Virtual Private Server) account.