For a production setup, it is recommended to use a SolrCloud cluster or Solr master/slave index replication. With Solr master/slave index replication one Solr instance - the master - handles index updates, while one or more other Solr instances - the slaves - handle high query load. Solr slaves periodically replicate index changes from the Solr master. Such a setup allows the distribution of high query load across multiple Solr slave instances and also provides basic fault tolerance for the query side. For replication without latency and better fault tolerance consider SolrCloud, which is described in Section 3.4, “SolrCloud”.

You can find more information about master/slave index replication in the Solr Reference Guide at https://lucene.apache.org/solr/guide/8_6/index-replication.html.