Server Cluster is a Microsoft technology to provide high availability on Windows platform. Though Server Cluster is very stable, it’s always recommended to have a backup in case any unexpected incidents occur, such as power outages or storage corruption. Please refer to the article below for how to back up and restore Sever Cluster in various circumstances.

 

Server Clusters: Backup and Recovery Best Practices for Windows Server 2003

http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/clustering/sercbrbp.mspx