Users sometimes use Solr’s SWAP command when prototyping a local Solr instance. This uses a secondary core which can be read while the primary core is being rebuilt. Then they discover a problem when they move to SolrCloud on SearchStax.
SWAP vs. CREATEALIAS
SearchStax deployments are all SolrCloud deployments. Use CREATEALIAS with SearchStax.
For more information, see CREATEALIAS: Create or Modify an Alias for a Collection.