Liferay DXP’s search solution is pluggable. Once you install a search engine and configure the appropriate adapter, you’re using a standalone installation of the search engine (usually installed on a cluster of servers) to create and manage your search indices. That means there’s really nothing special to do in the Liferay DXP installation when backing up your search engine’s data. In large part, these articles summarize the process and point you to the relevant documentation on backing up Elasticsearch and Solr, the two search engines supported for plugging into Liferay.