Move SiteCollections between WebApplications

edit: Please read this blog post before using 'mergecontentdb' data corruption may occur

On multiple occasions as a SharePoint administrator I have needed to move a Site Collection from one Content Database to another one. In the past this process was very painful and very manual. In this blog post I will show you how to move Site Collections between Content Databases with a single STSADM command using the "mergedbs" operation that was introduced in KB934525.

Why would I need to move a Site Collection to a different Content DB? This comes up for a variety of reasons. For instance, because of restore times, I like to keep my databases under a certain size. While I try to work with my Site Collections owners to plan accordingly sometimes they grow larger than we had imagined. When this happens I need to shuffle Site Collections around to keep my databases in harmony. There are other times when I would do it if it were more convenient. If Site Collections are not growing as expected, I may want to consolidate several into a smaller Content DB. I may also want to move less active Site Collections to Content DBs on slower discs, or move Site Collections to Content DBs that reflect geographic regions. Whatever the reason, in the past to move a Site Collection you had to go through the following steps manually;

1. Lock the Site Collection
2. Back the Site Collection up
3. Delete the Site Collection
4. Set all your Content Databases' maximum allowed sites to the number of current sites.
5. Set the Content Database you want the Site Collection to go into to allow one more Site Collection.
6. Restore the Site Collection
7. Unlock the Site Collection
8. Adjust your Content Database maximums to allow new sites to be created.

All of these steps could be done with STSADM so you could build scripts and move through the process quickly. In one of the recent security patches (KB934525) for WSS and MOSS Microsoft slipped in a new STSADM operation, mergecontentdbs. I assume this operation was added with the intention of merging Content DBs, but it can also be used to split them. This blog post will walk you through both uses. Let's start with the configuration below:

You can see in this screenshot that I have three Site Collections in two Content DBs; WSSContent and WSSContent2. Let's move http://barcelona/sites/stsadm from WSS_Content to WSS_Content2. If you get the help for the mergecontentdbs operation it looks like this:

We want to use operation 3, Read from file. STSADM has given us a clue about the file needed, it is generated from stsadm –o enumsites. I'll go ahead and run that and pipe it to a file like this:

This will produce a file, mysites.xml, that contains my site collections. To move http://barcelona/sites/stsadm we'll remove all of the other Site Collections except for that one from mysites.xml and save it. You don't need to worry about changing the Site Count at the top, or any of the other Site Collection information in the file, STSADM only grabs the URLs out. I only have two Content Databases so the decision of which database to move the Site Collection to is easy. What if I had many Content Databases? You can use the first operation, Analyze, to get an idea of how your Content Databases are laid out. Let's see how that looks:

You can see here where I got the idea to use the filename mysites.xml. The thing I love best about this screen is that you can just cut and paste the final command into your Command Prompt if you'd like. I think Microsoft did a great job with the usage on this command. One thing to note is that the –url parameter is NOT the URL of the Site Collection you want to move, it's the URL of the Web Application that the Site Collection is in. Since we've already created our file and edited it, let's go ahead and run the command.

That's all there is to it. After an iisreset we see that the Site Collection http://barcelona/sites/stsadm is now in WSS_Content2. You can confirm it by looking in Central Administration > Applications > Content Databases before and after you run the command.

I have one final thing to show you, what I imagine is the intended usage of mergecontentdbs, merging two Content Databases. If we use the second operation STSADM will simply move all the Site Collections from the Source database to the Destination database. Let's move all of the sites in WSS_Content2 back into WSS_Content.

I think that picture pretty well sums it all up. Now all the Site Collections in the http://barcelona Web Application are in WSS_Content, right where we want them. I think Microsoft did a pretty good job with this addition to STSADM. Enjoy it.

I'd like to give a special shout out to Joel Oleson for telling me to look for this little gem.

tk