The site_mappings attribute should be added to the master node's server.conf file when decommissioning a site in an indexer cluster. The site_mappings attribute is used to specify how the master node should reassign the buckets from the decommissioned site to the remaining sites. The site_mappings attribute is a comma-separated list of site pairs, where the first site is the decommissioned site and the second site is the destination site. For example, site_mappings = site1:site2,site3:site4 means that the buckets from site1 will be moved to site2, and the buckets from site3 will be moved to site4. The available_sites attribute is used to specify which sites are currently available in the cluster, and it is automatically updated by the master node. The site_search_factor and site_replication_factor attributes are used to specify the number of searchable and replicated copies of each bucket for each site, and they are not affected by the decommissioning process