Migrating an existing Drupal 7 site to Platform.sh
Contents:
Once you’ve setup the code for your site as a Platform.sh project, you need to upload your existing database and files directories as well to complete the site.
Import database 
With Drush (preferred)
You can use Drush aliases to import your existing local database into Platform.
The aliases here are examples.
Use the CLI’s platform drush-aliases command to find your own aliases.
drush @platform._local sql-dump > backup_database.sql
You can also sanitize your database prior to import it into Platform.sh by running:
drush @platform._local sql-sanitize
When you’re ready, export your local database and then import it into your remote Platform.sh environment.
drush @platform._local sql-dump > local_database.sql
drush @platform.main sql-cli < local_database.sql
When the process completes, you can visit the URL of your development environment and test that the database has been properly imported.
Without Drush
Export your database in an SQL file or in a compressed file.
Copy it via SSH to the remote environment on Platform into the /app/tmp folder which is writable:
scp database.sql [SSH-URL]:/app/tmp
Log in to the environment via SSH and import the database:
ssh [SSH-URL]
web@[PROJECT-ID]-main--php:~$ mysql -h database.internal main < tmp/database.sql
Import files
With Drush
You can use Drush site aliases to import your existing local files.
$ drush rsync @platform._local:%files @platform.main:%files
You will destroy data from [SSH-URL]:././sites/default/files and replace with data from ~/Sites/platform/sites/default/files/
Do you really want to continue? (y/n): y
Note:
Drush will verify that you are copying and overwriting the proper “files” folders,
so double-check that information before you type y to continue.
This step may take some time, but when the process completes, you can visit the URL of your production environment and test that the files have properly been imported.
Without Drush
Go to your Drupal root on your local machine and synchronize the files folder to your remote Platform environment:
$ rsync -r sites/default/files/. [SSH-URL]:public/sites/default/files/
Note:
The local files path may depend of your installation.
The path in URL may vary depending on what your .platform.app.yaml file specifies as the root path and files mount.
Directly from server to Platform.sh
If the files folder is too large to fit on your computer, you can transfer them directly from server to server If you have a firewall between the origin server and Platform.sh, you can use agent-forwarding to enable a direct connection:
$ ssh -A -t [USER]@[ORIGIN-SERVER] ssh -A -t [SSH-URL]
$ rsync -a --delete [USER]@[ORIGIN-SERVER]:/var/www/drupal/sites/default/files/ public/sites/default/files
Note:
If you are using a Mac OS computer,
you might experience issues where files with non-ascii characters in them don’t work after transfer
because Mac OS X uses decomposed form (like a + ¨ = ä, a form known as NFD),
not the usual composed form (ä, a form known as NFC used everywhere else).
One workaround is to use the direct server-to-server transfer method mentioned above.