Users: Just do not delete site files from your local disk while you are cleaning your system.Some additional KB / MB won't slow down your computers. It's the natural backup. Don't modify files directly on FTP. Do it locally first. Then upload onto FTP. Remember also about making backup of your database. You can do it with phpMyAdmin. Some CMS have also this feature.
Only
SQLite driver is enabled in PDO.

I would be pleased if you enabled MySQL driver if it is possible.

I hope there are more PHP programmers among DHost community and they care about data security and the progress. Using old and outdated mysql_* functions is more dangerous and does not offer new features like: transactions, prepared statements, foreach($query as $row), more modes of fetching rows (e.g. arrays, column, object), etc.