The WPMU version of WordPress allowed for the creation of multiple websites to be hosted within the same install. This was to allow quick creation of users websites that were hosted on WordPress.com. .. yes most of the code in the WordPress.org package that you install to make your website work is the same product that runs millions of websites on www.WordPress.com .
What are some of the considerations you should take into account when deciding to use a WP3x Multisite Network?
First you should understand that although you are getting most of the same code that WordPress.com is using you are not getting all of the optimization behind the code that allows large numbers of websites to be hosted on a single server.
Along with code optimization WordPress.com has quite a bit of Server Tuning.. they use different HTTPD servers then you will most likely use on a shared, VPS or even a dedicated server. Their PHP, MySql and Memory Caching is highly tuned to provide quick response. This is something that takes a lot of skill to manage and setup.
With that in mind don’t think that you can simply enable the option and begin to host thousands of sites.
Not to mention WordPress.com has a lot of limitations on Plugins, Themes and other options that users can make use of.
If you start loading up the options for your members then you will also load your server.
Corruption of the Database is my primary concern with any multisite install. Quite simply there are a lot of flaky plugins out there not to mention people that use or develop themes that directly access the database instead of using WP Calls.
If you have corruption of your database you could end up with all of your sites going down and recovering from that may be close to impossible.
Again these problems are not seen on WordPress.com because they test everything extensively before deploying it but you can never tell what one of your users is going to do at 3am.
Limits on Account Functions
If you install all of your sites with their own cPanel account then your users can make use of all of the features found in cPanel and add ones on their own. They can create Email Addresses and manage Domains or check server logs.
If you place all of your users on a MultiSite then users will be limited in the available functions within their account. They may come to you to make changes and expect you to do it for free. Nothing is free.. but allowing a customer to do something as simple as setup an Email account on their own will cut down on support labor time and headaches.
What is the best use of a WordPress Multisite Network?
Networks are best if you are creating websites of the same type or support subdomains for the same site… or maybe a membership site where you allow members to have their own site.
If you are deploying sites of dissimilar content you may have dns glitches with the top site or primary domain showing up intermittently while subsites load.. so you probably want the primary domain to be hosting related or something of that nature that announces the sub sites. In other words you don’t want the primary domain to be a porn site if you are hosting subsites for churches….
Personally I would never build a network unless i was building a membership site like ning .com
but they could be useful for a complement of site subdomains
where the primary goal is to separate content to make it easier to manage
where each office would have an administrator and support their own content.
Both of these options are primarily in-house use of multisite networks and this is probably best for most users.
You should not be scared of creating the next best social network for your users by using Multisite Networks but you should understand that the level of support for these sites will be just as high as independent installs.
You will find it more difficult to backup single user accounts with dozens, hundreds or thousands of similar tables in your database. Most likely you will need to resort to WordPress Export or a Plugin vs PhpMyAdmin.
You will also need to improve your testing mentality and never allow a plugin on a live server that has not gone through testing on a dev server.
All of your files will need to be watched for exploits. You don’t want the actions of one administrator taking out all of your clients sites.
You should consider a dedicated server and using nginx and memcache along with other features that will optimize and improve the function of your site.
Although managing 100 multisite network sites may be easier then managing 100 independent installs your ability to get to the point where you can support multisite in that level of hosting will be exponential.
Most of the information that you need to learn will be undocumented. This is simply a fact of people who are doing it not wanting to release months or years of knowledge for free. And that as your site changes and expands unknown problems will occur that no one has ever stepped into.
If you are contemplating a Large membership site … start by using multisite for the methods I described above first.
Learn how to upgrade plugins across 5 to 10 related sites.. it is more difficult then a click. Then dive deep into user management and control. Finally brush up on DNS and Server Optimization.
Then when you are ready have a site where you need to deal with 50 or more users all wanting some type of support and changes to their sites.
After that consider all of the work you will need to perform and you may find that like me… for the most part assigning one administrator from the company you are working with and one full install in a cPanel account will get you by for most things.