About the high availability features in Security Center - Security Center 5.8

Security Center Administrator Guide 5.8

Security Center 5.8

High availability is a design approach that enables a system to perform at a higher than normal operational level. This often involves failover and load balancing.

To ensure that there is uninterrupted access and data protection for your system, Security Center offers the following high availability features:
Directory failover
Ensure that the Directory role remains available when its primary server fails. The Directory role handles failover for all other roles, so it is important that the Directory role remains available at all times.
Directory load balancing
Additional benefit of Directory failover. Up to 5 servers can be assigned to the Directory role to share its workload. All servers that are set up for Directory failover are automatically used for load balancing.
Database failover (only for Directory role)
Protect the Directory database, using one of the following methods:
Backup and restore
Regularly backup your database, and restore it if a failover occurs.
Microsoft SQL Server Database Mirroring
The database instances are kept in sync by Microsoft SQL Server.
Archiver failover
Ensure that the Archiver role and video archiving capability remains available when the Archiver’s primary server fails.
Other role failover
Ensure that other roles in your system remain available when their primary server fails. If the role database must be protected, you should consider one of the following third party solutions: SQL Server Clustering or Database Mirroring.
NEC ExpressCluster X LAN
Third party solution for roles that do not support failover.
Windows 2008 Server failover cluster
Third party solution for roles that do not support failover.

Other ways you can ensure high availability are to detect problems early, and prevent those problems from reoccurring.