WPMU is out, Virtual Multiblog is in

Apr 23, 2009   //   by Hackadelic   //   Featured, WordPress  //  9 Comments
This entry is part of a series, The Quest for a Multi-Blog Solution»

MultiverseAlea iacta est. The dice has been cast. I’m giving up on WPMU. Definitely. I will be using Virtual Multiblog instead. Definitely.

I am absolutely delighted by Virtual Multiblog (VMB). It’s the kind of brilliant, synergetic solution that leverages existing features in novel, unusual ways, to achieve wonderful new things.

And man, works it smoothly? I mean, when some software package (VMB) is up to change another software package (WP) in such fundamental ways that it switches the very paradigm from single to multi-blog, I expect at least some problems. But nope! Whatever I thought of doing with and on top of VMB, it worked flawlessly.

I’m not sure if I am in any way a “statistically representative” person regarding intuition, but operating VMB was ultimately intuitive to me. Absolutely straight. Actually, so straight, that I partially automated the process of creating new blogs. Currently, the automation is implemented in Python, and must be run from a shell. I’ll be porting it to a WP plugin soon.

To me, the best thing about VMB is: It doesn’t enforce any up-front decisions, unlike WPMU. It allows your blog family to evolve in a very organic way, by allowing for any combination of domains, sub-domains and sub-directories to be added at any time with ease. You don’t even have to start with VMB installed in the first place. You can add it at the moment you need your second blog.1

Another cool thing is that you don’t risk any incompatibilities with existing WP themes and plugins. Unlike WPMU, which is almost, but not entirely, compatible with WP, VMB boosts WP itself to a multi-blog engine. No surprises. (Update: The only exception are plugins that make changes to .htaccess, but they are fairly rare. See Stephen’s comment down below.)

One more thing I love about VMB is the future-proof way it achieves its objectives. It doesn’t change or rely on something in the depths of WP. Instead, it behaves like a caller to WP. In a way, VMB is to WP what a shell is to a program. The shell may call a program with different parameters, and with environment variables set to different values, but it doesn’t change how the program works. Conversely, new versions of the program don’t break the shell.2

As a consequence, your blogs always run on the latest and greatest WP version. No lurking security holes that aren’t fixed in WPMU yet. I imagine it may come close to a nightmare to know there is a serious security breach in WPMU that’s already fixed in WP. Wouldn’t that drive you crazy?

At this point, I would like to list some “con’s” about VMB. It’s just that I can’t think of any.3

I’m rarely so exalted about a piece of software. I have pretty high standards about quality, conceptual clarity and elegance of software solutions. On average, the best I can tell about any piece of code is that it is solid. Not this time. My highest compliments to Stephen Rider, the author of VMB, and Allan Mertner, on who’s original idea VMB is based.

What’s next?

Well, as it stands, with VMB there is no real need to change anything about my blog. I could defer installing it until I’ve designed a new blog locally and purchased a new domain. I will do the switch now, though. Because (a) I should eat my own dog food, and (b) I want to take the chance and re-install WP in the hope to get rid of some weird effects I’m having with it lately.4 It is that latter part that’s cumbersome, and my main activity focus right now.5 When I’m through with that, and the “repaired” blog is online, I’ll post a tutorial how to set up multiple blogs with VMB, and probably blog about the reparation process, too.

So see you later, visitator. 🙂

  1. There is a name for this operation principle: Just-in-time . It is one outstanding feature of good usability not to enforce things, but ensure things are available when they are needed. []
  2. In reality, there is a small chance that a future version of WP could break VMB, but it is highly unlikely. []
  3. I won’t complain about the fact that it doesn’t have a UI for adding blogs. It gives me the chance to implement one. []
  4. For some reason, the widget admin page behaves very strange. []
  5. It seems as if the wp_options table is slightly damaged, so I can’t just copy the data. I’ll have to re-apply every setting manually. []


  • hello,

    thanks for creating VMB. Unfortunately, I can’t seem to get it to work with WP 2.8.2. I have tried ceaselessly by following each line in the readme file, but it still won’t work.

    Foremost, after activating the plugin in the plugins admin page, and clicking on the Multiblog Kit link in the tools sub-menu, I got this error message:
    Virtual Mutliblog Not Found

    To use Virtual Mutliblog, it needs to be uploaded into the wp-content directory.

    Download Virtual Mutliblog at striderweb.com, or read a review about its features.

    This prompted me to make a copy of hackadelic-multiblog-kit in the plugins directory and copied it to wp-content folder. I even CHMODed both wp-content and hackadelic-multiblog-kit to 777 including all the files and folders, but all to avail.

    Is there a way you the author or anyone else can fix this up or give me detail instructions on how to manually configure VMB and make it work.


    • Paul, there are two complementing systems. Virtual Multiblog (or VMB) is the technology developed by Stephen Rider. Virtual Multiblog Kit (or VMBKit) is a plugin I made to simplify the handling of VMB. VMBKit needs VMB to operate. If it’s not installed (at it’s default location), you’ll get the mentioned message. Instead of making a copy of VMBKit, download and install VMB.

      Hope this helps.

  • Ray —

    Actually, WordPress allows you to set your wp-content directory, (or, separately, the plugin directory), via a CONSTANT in the config file. This works just fine in VMB, so you *can* have separate plugin or wp-content folders.

    You can define:


    Heh. I *really* need to update the VMB docs! 😉

    • Stephen, I’m actually sure the VMB docs do contain that information. 😉

      I knew that you can define where these dirs are, but I’ve found there are several reasons not to do that.

      – If you are after a single code base to maintain, it makes more sense to to have a single pool of plugins.
      – AFAIK there is no WP_THEME_DIR constant, so you must merge themes anyway.
      – The directory relocation feature is rarely used, so I suspect some plugins and/or themes may have trouble with it.
      (For ex. I’ve frequently seen this in WP plugin code: ... = ABSPATH . '/wp-content/...'. Such code would break.)

      All in all, I wouldn’t really recommend to use this feature unless you absolutely must.

  • I’m looking forward to this plugin as well!

    I have a site that runs on two WordPress installs.
    The ability to use one install base would be great!

    My question is:
    (This is probably better directed to Stephen than Zoran, but…)

    Would it be easy to take an existing WordPress install (or two) and use VMB to power it?

    • Ray, definitely: You CAN start with a single WP blog and extended it at any time by VMB. That’s what I meant by:

      You don’t even have to start with VMB installed in the first place. You can add it at the moment you need your second blog.

      I already did all that on my test server and it worked flawlessly.

      Also, you could keep your second blog’s database and let it be powered by your first WP installation. You’ll have to merge the themes and plugins directories of the two blogs though.

  • Oh, quick note regarding plugin compatibility with VMB — I have found one thing that can make plugins incompatible: making changes to .htaccess

    This is fairly uncommon among plugins, but (for example) I don’t think there are any caching plugins that work with VMB right now. The fix is probably just a clever hack to the mod_rewrites, but I haven’t figured it out yet.

    • Thanks for the hint, Steven. There is my one and only “con” then. 😉

  • I want that plugin! 😉

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