How to change database for existing site collection in a sharepoint web application?

Question

I have created 2 site collections on one web application. How do I now assign a different database for these 2 site collections?

Answer 1

For this process to work, the following must be true

1. The destination content database must already exist.
2. The source content database and destination content database must be located on the same instance of SQL Server.
3. The source content database and destination content database must be attached to the same Web application.

Steps

• Add a content database to a web application by using Windows PowerShell
• Move your site collection to another content database

To add a content database to a web application by using windows PowerShell

• Start SharePoint 2013 Management Shell -Type in the following command

   New-SPContentDatabase -Name <ContentDbName> -WebApplication WebApplicationName
  

• Replace <ContentDbName> with the name of the content database to create

• Replace <WebApplicationName> with the name of the Web application to which the new database is attached

To move your site collection to another database:

• At the Windows PowerShell command prompt, type the following command:

  Move-SPSite <http://ServerName/Sites/SiteName> -DestinationDatabase DestinationContentDb
  

• Replace <http://ServerName/Sites/SiteName> with the name of the site collection.

• Replace <DestinationContentDb> with the name of the destination content database.

Answer 2

With PowerShell. Move-SPSite

Move-SPSite http://servername/sites/sitename -DestinationDatabase ContentDb2

Be aware that you have to do an IISreset on all the servers in your farm after you move a site collection to a different content database, which means downtime for the end users.