WordPress Multisite lets you create multiple WordPress websites that all use the same set of themes and plugins.
It might appear to be a great way to make maintaining multiple sites more efficient, as you can update the WordPress core, themes, and plugins once, and they are updated for all sites.
But in practice, the hidden downsides of Multisite can outweigh the benefits in many situations, and the use cases are more limited than they might appear.
The Benefits of WordPress Multisite
The main benefits of WordPress Multisite are reducing maintenance time and having a common codebase for multiple sites.
If there is a WordPress core, plugin, or theme update, you update it once and it’s updated for all sites in the network.
In some situations, this can be very beneficial. But, let’s look at some of the hidden downsides.
The Hidden Downsides
There are some serious downsides to using WordPress Multisite that might not be immediately apparent.
1. Database Size
If your sites are huge, and this is often the case in e-commerce sites, then you’re multiplying the size of your database by the number of sites in the Multisite network. This can slow down the performance of ALL of the sites in the network.
I would never put two WordPress sites with huge databases on the same Multisite network. Since the database on e-commerce sites can get really huge, I would avoid putting any e-commerce sites on Multisite.
In my experience, WP Multisite database tables tend to crash more often than stand-alone WP databases. A crash on one site can bring the whole network down if it happens in one of the shared tables.
2. Increased Security Risk
If one of your sites is subjected to a DDoS attack or hack, all sites in the network can be affected. Someone can take down your entire WordPress network by attacking one site in the network. Basically, your attack surface area is multiplied by the number of sites you have in the network.
3. Plugin Incompatibility
Not all plugins work on WordPress Multisite. And, not all plugins work the same way on Multisite. Wtih some, you activate them in the parent site, and in others, you activate them in the individual child sites. In general, most plugins are used a lot less on Multisite, so the plugin developers are not likely to test them as thoroughly for Multisite. Bug fixes might come slower as well.
Some plugins require you to purchase the paid pro version for Multisite compatibility.
4. Difficulty in De-Coupling
For some reason, I haven’t see a lot of automated tools or plugins for extracting a Multisite sub-site into a stand-alone WordPress site. Think about whether there are any scenarios that would require you to do this.
Here are some articles I found on how to do it manually:
This is not something I would recommend for causal WordPress users. Do you know of a plugin that does this? Please comment!
5. Difficulty in Backing Up and Pushing to Staging
Many of the tools for backing up and copying sites don’t work out of the box with Multisite. WP DB Migrate Pro does have a Multisite Tools Addon but it requires purchase. Overall, the migration process is longer and more involved with Multisite. Since the databases and media libraries are larger, backup scripts are more likely to time out, potentially turning a one-click process into a multi-hour ordeal.
If you do need to make a backup of a Multisite network, I recommend the Duplicator Pro plugin:
6. Greater Developer Expertise Needed
WordPress Multisite requires more expertise in development and maintenance. That means you’ll have a smaller pool of WordPress developers to choose from if you have problems and you might have to pay more.
As a developer myself, it means I have to spend more time figuring out how to do things that I could do much quicker on a regular WordPress install.
Basically, WP Multisite makes some of the easy tasks like updating plugins easier, but makes the hard tasks (like debugging problems or migrating) even harder. Not a good tradeoff in most cases!
7. Shared Users
I have one client that has a Multisite network of WordPress membership sites, each with different admins who manage their sub-sites’ users.
But, when a local admin deletes a user locally, that user still exists in the Multisite database, and they can’t re-use that email address. So, I have to go in as the Super Admin and delete the user globally. Luckily, this doesn’t happen too often, but it is easily avoided with separate sites.
8. Putting All of Your Eggs in One Basket
In general, I don’t like putting all of my eggs in one basket. If a plugin update has a problem, or if you introduce a fatal bug in a theme update, it will affect all of my sites that use that plugin or theme. It’s bad enough to bring one site down with a bad update, but it would be horrible to bring ALL of my sites down. I don’t like having sites chained to each other unless the benefits outweigh the costs.
Yes, I know you’re supposed to test plugin updates on a staging site. But many people don’t. If you’re one of those folks who just pushes the Update button when a new plugin is available, I really wouldn’t recommend Multisite!
Why the Benefits May Not Be As Great As Expected
The big benefit of Multisite, easier site administration, might be insignificant if you have unique sub-sites. That’s because, if your sub-sites are all different from each other, then the main time-sink in the update process is not pressing the “Update” button. It is testing to make sure the update didn’t break one of the sites.
Using Multisite doesn’t excuse you from having to test each of your sub-sites individually (unless your sub-sites are truly very similar to each other). So there are diminishing returns if your sub-sites are unique.
When I Would Not Use Multisite
Here are some specific cases where I would not use Multisite:
- Sites that don’t share themes
- Sites that use different themes or that require individual theme customization
- Sites that have different “owners” who might want their own customizations in the future
- Any site with a huge database
- Sites that require high security, or sites likely to be attacked (i.e., religious, political, celebrity sites)
- Sites that might need to be split off into separate sites in the future
- Any mission-critical sites where bringing down the entire network would be disastrous
- Sites where fastest load time is needed
What to Use Instead
There are many WordPress administration services out there such as ManageWP that let you manage multiple stand-alone sites similar to how you manage a Multisite network without the downsides of Multisite. These allow you to do updates across many sites at the same time, if that is what you want to do.
When I Would Recommend WordPress Multisite
It may sound like I hate Multisite, but there are actually some situations for which the benefits outweigh the disadvantages.
1. Lots of Simple Child Sites with the Exact Same Custom Theme
I have one client with a bunch of one-page sites that use the same custom theme. Furthermore, that theme changes often due to API changes.
In this case, Multisite has been a time-saver, as each theme update requires me to FTP up custom theme files. With Multisite, I just do it once. And, since the sites are basically one-pagers, testing is easy, and there’s no danger of database bloat or the media library getting out of control.
2. Lots of Nearly Identical Child Sites
I haven’t encountered this exact scenario yet, but let’s say you own a franchise where each of the franchise owners needs to have a simple website with a common theme. And, let’s say customizing individual themes is prohibited in the contract. This might be a good candidate for Multisite.
3. Your Web Host Doesn’t Allow WP Installs in Subdirectory
This is actually where I do use Multisite. My web host does not allow the installation of WordPress in subdirectories. So, pretty much the only solution is to use Multisite.
What do you think of Multisite? I’m sure I missed some cases where it is beneficial. Please comment below! – Brian