As time passes, you might need to optimize or rebuild your search index. High availability search indexes allow you to take one search appliance out of service for required maintenance while the other search appliance continues to operate.
For more information about how to perform needed maintenance on the search index, see Managing the Lucene Index
in the Filr 2.0: Administration Guide.
For information about an example setup, see Completing the Cluster Setup
in the Planning and Deployment Best Practices Guide.