WordPress Multisites or Multiple WP Single sites?

Question

So I am pondering over a decision to use WordPress Multi-Sites or just use Multiple WP Single sites. The reason is that the company site is broken down into multiple departments.

Maindotcom (WP SITE)
 /about
 /department1 (WP SUBSITE)
 /department2 (WP SUBSITE)
 department3.maindotcom (WP SUBSITE)
 /contact
 /blog

I would like...

• to Have a Super admin that has access across all wp sites.
• to use both, subdomains and subfolders, in the chosen setup (see example above).
• to know which is better for SEO?
• for all sites to share media folder
• for all sites to share the main template file
• have maximum compatibility with plugins
• each site to have its own database.

I have looked into using WP HyperDB which has the ability to add on remote servers and Master/slave setups.

And I have seen solutions to share same user across multiple installs using HyperDB: How to use hyperdb to separate and share a user dataset between wordpress installs?

Please let me know any solution

Answer 1

Rather than post this as a bunch of comments, I'm going to make this an answer.

Your requirements/questions:

to Have a Super admin that has access across all wp sites.

That's a hallmark of Multisite.

to use both, subdomains and subfolders, in the chosen setup (see example above).

You can accomplish this with something like the Multi Network plugin, as I understand it.

to know which is better for SEO?

Someone else would have to answer that; I'm not an SEO expert.

for all sites to share media folder

This isn't something that WordPress Multisite does, so you'd need to find a plugin (or build one / hire someone to build one) to do this. You'd be in the same boat if you use a group of single-site installations, too.

for all sites to share the main template file

You can use the same theme on all the sites in a Multisite network; you can even set a default theme for new sites in the network using the WP_DEFAULT_THEME constant in wp-config.php.

each site to have its own database

Multisite separates sites into their own tables in the database, with a common table for the users (all users are able to be added to any of the sites). eg, if you're using the default wp_ prefix in your database, then for these sites:

Maindotcom (WP SITE)
 /about
 /department1 (WP SUBSITE)
 /department2 (WP SUBSITE)
 department3.maindotcom (WP SUBSITE)
 /contact
 /blog

... your database would be something like this:

// tables for maindotcom
wp_posts
wp_postmeta
wp_options
...

// tables for maindotcom/department1
wp_2_posts
wp_2_postmeta
wp_2_options
...

...and so forth.