Cannot overwrite file: /var/lib/mysql/ibdata1 when using Percona xtrabackup
You should be restoring to a completely empty folder - you need to remove all the content (files and folders) from the target folder before doing the restore. Xtrabackup contains the entire system, not just a particular database. As always, test the restore on your test environment before attempting on production! And remember to shut down MySQL before attempting the restore or cleaning the target folder...