Regardless of whether it's a single system or small number of systems, the result is catastrophic, and your application will probably be unavailable for a period of time.
无论是单个系统还是少数几个系统，结果都是灾难性的，您的应用程序可能在一段时期内不可用。
2
The backup may be an online operation, but the restore is offline and the time that the database is unavailable may be unacceptable given your availability requirements.
If any given server is unavailable or too busy at the time the request arrives, the cluster transparently passes the request to a server capable of handling the work.