Migrating a website software version is one of the highest risk task a webmaster encounters when managing a website. Drupal 8 Migration? Here is a small guide with various details. Let’s start with basic info : The content of your site does not live in your Drupal installation. It lives in a MySQL database which is managed by your Drupal installation. This database will sit somewhere on your server, as determined by your web host. (As an aside, I never did figure out where Dev Desktop puts the database on your computer at home. It’s a mystery.) Anyhow, the exception to this is that the images within your site do live in your Drupal installation, they are in the sites folder somewhere (depending on your settings), with Drupal keeping records of them in the database.
First of all, make a list of all the contributed modules on your current website. Next, check whether these modules have a Drupal 8 compatible version. In case of unavailability of the Drupal 8 version, the migration process will suffer. Fortunately, Drupal 8 has come a long way and many of the major modules now do support Drupal 8. You can check all the available update paths through the Migrate UI modules. After proceeding, you will be brought to the Migrate UI where you can check all the potential issues and errors that you might encounter as well as all the available and the missing paths. Go through this screen and when satisfied, start the migration.
If you’re migrating from a previous version of Drupal, start with our Preparing for a Drupal-to-Drupal Migration tutorial. From there you’ll learn how to perform a basic update using either the built in UI or the contributed Drush commands, as well as some common best practices to help things go as smoothly as possible. If you’re looking to customize your Drupal-to-Drupal migration a bit, continue through the tutorials on writing custom migrations, and then we’ll go in-depth on how to use those skills to tailor the Drupal-to-Drupal update process to your specific use-case.
The steps above outline how to get a distribution minimally installed on an existing site. But you’ll still have a lot of work to do to reconcile your existing site content and structure with what has been created by the distribution. Here are a few tips to get you started–but you should begin with the assumption that there will be lots more you’ll discover and need to fix. If the distribution is installed from scratch, we can be sure that the components we’re creating won’t conflict with existing components on the site. But when we’re converting an existing site into a one based on a distribution, there’s the potential that a component we’re creating will have the same name as one that already exists on the site. In certain cases, such a conflict can cause a site error that’s difficult to resolve.
Update your site to the latest version of Drupal 6 (core and contributed modules). Before upgrading to Drupal 7, disable and uninstall modules you know you won’t be using in the new site. To help determine which modules to uninstall, you could review the list of modules included in the distribution, which often are found in the download in the directory profiles/[distribution_name]/modules. If a given module is not in the distribution and you don’t foresee needing its functionality on your new site, you may choose to uninstall it.
Without getting too deep into the weeds, Drupal 8 is much different than previous versions of the CMS, hence all of these upgrade implications. That’s because the Drupal community decided that the platform needed much better core standards and functionalities. Thus, Drupal 8 is essentially a rebuilt version of Drupal with the entire system moved to symfony php, a framework that any versions in the foreseeable future will also be built on. So even though upgrading to Drupal 8 from Drupal 7 might be a painstaking process, updating to Drupal 9 and beyond should be a breeze – that is, once you are already on 8. See more details at Drupal 7 Upgrade.