Solr operator make it easy to set up all the building blocks needed to run a redundant high availability setup with the added benefit of higher read request capacity. Additionally a special setup is neede with our cluster because of problems between solr and our default storage class based on glusterfs.
Glusterfs slightly alters the access time when it makes the required copies of the data for redundancy. Solr does not allow that.
As it is actually better to use as little outside storage redundancy setup as possible and instead trust the very capable sharding and redundancy provided by Solr.