Mapping a domain within a mapped domain

So, I was wondering whether or not it would be possible to actually map a domain within a mapped domain on UMW Blogs, and I finally got my answer at the Faculty Academy workshop I ran on domain mapping.


What the hell am I talking about? Well, it’s pretty simple, we currently have two WPMu sites running within UMW Blogs. The straight UMW Blogs site, as well as (a.k.a Longwood Blogs), which is a mapped domain/site on UMW Blogs using David Dean’s awesome Multi-Site Manager plugin. So, in other words, is a publishing platform within a publishing platform that the library folks and faculty at Longwood are using for a pilot and some experimentation. (And it was excellent to see so many people from Longwood in attendance at Faculty Academy getting a sense of what’s happening at UMW through this tool.) The best thing about this setup is that it’s simply running off the same install/database as UMW Blogs but with it’s own domain and dynamic subdomains. (Stop and think about the implications of this for a second: one upgrade, one set of themes, one group of plugins, distributed functionality, and potentially more sharing and lower costs for everyone involved—for more on this here is my post about this experiment from November.)

So my question was, can a student or faculty at Longwood just as easily map their own domain on their site, for example  mapping onto as folks here on the UMW Blogs domain can thanks to Donncha’s Domain Mapping Plugin. And the short answer is YES! I was concerned there may be some issue with the multi-site manager plugin, or some larger .htaccess issue, or even a multi-database issue, but nope, none of that is of concern. It works like a charm. Now I just need to figure out how to filter BuddyPress by domain on a multi-site setup like UMW Blogs, and this thing is some amazing potential for collecting and share data amongst and between students, faculty, and staff from a wide-range of colleges, universities, and, dare I say it, K-12.

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6 Responses to Mapping a domain within a mapped domain

  1. Scott says:

    Hey Jim,
    This is very cool. We have one server using the Domain Mapping plugin (I think the Multisite might have been the way to go now). One thing to watch with the Domain Mapping plugin is it will generate ALOT of queries on your DB which I just discovered last week… I am talking potentially hundreds per page (I saw 800 on one). You might want to try running using to see for yourself. If the site/server becomes busy you might have problems because of the load on MySQL if you are not caching the Database queries etc using Qcache.

  2. Michelle says:

    Hi Jim,

    We’re wondering at Suffolk if domains can be mapped that exist outside of your install. For instance, will be switching to WordPress but using it’s own WP (not MU) install. Can we have that show up on Blogs @ Suffolk University as it’s own blog without hosting it on our mu install? Does the plugin work this way and have you ever tried it?

    Also, we’re considering (as is probably necessary) switching from sub-directories to sub-domains. How did this go for you guys (I know and have read some blog posts about it before). Or for anyone else out there?

    Why did you switch and could you reference some of the advantages/disadvantages and the reason for the move? (I realize that Donncha’s plug-in probably plays most nicely with “a domain of one’s own” – an idea which we really like – but was the ability to map domains the main reason for the switch?)

    Thanks a bunch as always!


    ps. I just told a colleague before I came here that I was going to look for answers to some of our questions on “bavapedia” 😉

  3. Reverend says:

    Thanks for this, I haven’t thought about this and this could create an issue. Why all the extra resource intensive queries? Also, what’s interesting is that the mutli-site manage is being used in conjunction with Donncha’s Domain Mapping Plugin. So, for example, you can create all these separate wpmu sites within one database, and still allow anyone and everyone to map their own dom ains, it seems so brilliant to me. I see the two as key if a systems is supporting 10 or 15 campuses and they all want their own install and to share across schools, etc. I’ll download debug queries and check it out, but I would love to talk with you in more detail about approaching this more intelligently so that if it does explode we are ready. I can’t thank you enough, I really need someone who is smart about all this stuff showing me what’s up 🙂 Let me know if and when you can talk, or even some consulting about some larger issues with WPMu on our scale would be in order.

    Bavapedia, huh? You know I am stealing that right? All this after having to admit to Scott just how much I don’t understand about what I am talking about.

    1) To your first question about Ford hall Forum, I haven’t imagined this process in reverse, in other words, I think the benefit is having this site within your WPMu install so you don;t need to update and manage yet another site. That said, I think if you want the address to be you really wouldn’t need to change it, but if you want it to me forhallforum.suffolkblogs…. then you might as well just load it on Suffolk Blogs. Now, that said, you can also pull all the posts from the FCord hall Forum Blog into an individual blog using FeedWordPress so you can have a copy of that site on Blogs @ Suffolk without any additional maintenance saving pull the feed. Does this make sense?

    2) We went from sub-directories to subdomains when we moved from to And given we had about 100 blogs on ELS Blogs the transition was easy, and we asked people to import their work via the import feature for WordPress as they see fit. Thos who didn;t want to kept their work on ELS Blogs, which is still up and running. Now we moved domains, which is a bit more complicated, for subdirectories to sudbomains it would be an Apache switch, and I think it wouldn’t be too bad. I haven’t thought about it in a while, but if you are seriously considering it let me know and I’ll find out the details. And if anyone else has done this recently please chime in.

    3) I went to subdomains back in 2007 because that was the only setup IT Damager’s sitewide feed for posts, comments, and pages worked for at the time. That has since changed however. The only other advantage is that as of now, though I may be wrong, Donncha’s plugin for Domain mapping only works with dynamic subdomains. Finally, I really like the whole subdomains aesthetic, because it makes the URL look neater.

    I hope bavapedia hasn’t disappointed, though I feel like I always raise more issues than answers 🙂

  4. Scott says:

    Hi Jim,
    They are not huge resource intensive queries there are just a lot of them so it adds up, I think it has to do with all the link rewrites. Many others report the same problem. Probably a solution out there but I have not found it yet. I did a short post on basic Qcache set up: this is a good intro Qcache: sort of limits the damage and easy to setup.

    Are you in Van for the Open Ed conference? Hopefully you can hook up with our group here and we can talk shop. You are doing a lot of things we are keen on implementing.


  5. Reverend says:


    I will be in Van for OpenEd, and I would love to sit down with you all and talk this through. Plus, I want to talk to you about the domain mapping plugin, because one of the things it doesn’t do is re-write the various URL values in the database tables for a specific blog when the domain is mapped, which leads to some bad re-directs and the inability to upload files. I’m fixing this one-off in the database right now, but this needs to work out-of-the-box as this option becomes more popular.

    So, in other words, Vancouver. August. You. Me. Novak. Velkro. And every and anyone else, like perhaps that D’Arcy Norman character. Though I don’t think he is a fan of mine any more after my recent tweets promoting the values of the USA 😉

  6. Michelle says:


    Thanks a bunch, your info has helped. Not sure what to do about Ford Hall Forum as they want to manage their own site. Maybe the multi-site manage option you reference would work for that, as long as they could be admins and have FTP access to their own folders but not the general Suffolk ones. Does it work that way for Lincoln on UMW? Alternatively, I could just do a better job convincing them to host it with us… I did finally talk them into WP for a site over Dreamweaver. They definitely want to keep their domain, and their site will be CMS-like, too complicated for just feedwordpress, but that might have to do, even if we just grab their latest “events” tag feed or something.

    As for the upgrade and potential switch from subdirectories to subdomains, I’m a little nervous about that, so I’ll have to investigate more. Does BuddyPress work better with subdomains? We really want to take advantage of that to the fullest. Also, I really like how donncha’s plug-in allows for domain mapping and we could really use that in a lot of ways on our installation. I’ve heard there was something else out there for sub-directories and mapping but not as good. I’m also a fan of the cleaner urls, too.

    Wish I had the time and resources to go to conferences and meet up with all the people having conversations about this stuff. Maybe one day… I was the only instructional technologist at our U until 2 months ago (we have one more now) so I’m pretty non-stop with all things big and small, from WPMU to podcasting to blackboard (ugh). WPMU is my favorite by far.

    bavapedia: no one ever thought of that before? I’m surprised! You most certainly must use it! 😉

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