My suggestion is to not store it in a network file system, or if you really must then apply the recommended architectures we suggest in the documentation.

Read our documentation, especially the sections about JMS master/slave architecture, or the alternatives using JGroups and/or Infinispan. http://hibernate.org/search/

Yet another alternative, upgrade to latest Hibernate Search version and use Elasticsearch for the storage. Elasticsearch is better suited to un in a distributed environment.