Doctrine: String data, right truncated: 1406 Data too long for column 'column_name' at row 2

It is only one of the way. If you want to convert field to another type, you can fix it with changing values length in the database, according to your changes length.

Change CKeditor height in Symfony

add theres rows in \egeloen\ckeditor-bundle\Resources\views\Form\ckeditor_widget.html.twig:

<script type='text/javascript'>
    CKEDITOR.config.height = 700;
</script>

And don't forget to php app/console assets:install --symlink && php app/console assetic:dump && php app/console cache:clear