The vCenter Server and vCenter Server database need to be analyzed. The database is critically important as it contains the “corporate knowledge”; information on licensing, authentication, resources & locations, historical information are all maintained by the database. Loss of the database will require a rebuild of the environment.
The vCenter server populates the database and uses that information to manage the environment.

There are several supported options for improving the availability of the vCenter Server:

1. Implement vCenter Server as a Virtual Machine and use migration and HA tools such as vMotion, HA and DRS to maintain it.
2. Setup protection against application or operator errors, operating system or hardware failure, or external events using VMware vCenter Server Heartbeat
   Heartbeat proactively monitors and protects all components of vCenter Server at the application and service layer with automated and manual failover and failback and the ability to restart or restore individual services. Heartbeat provides the same level of protection for the vCenter Server database, monitoring and protecting the Microsoft SQL Server database associated with vCenter Server, even if it’s installed on a separate server.
   
3. Implement a 3rd party clustering solution such as MSCS (Microsoft Cluster Services) and VCS (Veritas Cluster Services) and if you have an existing Microsoft SQL or Oracle RAC cluster implementation then clustering the database with one of these is an option.