As mentioned above, JCR Indexing is based on Lucene indexing library as underlying search engine. It uses Directories to store index and manages access to index by Lock Factories. By default JCR implementation uses optimal combination of Directory implementation and Lock Factory implementation. When running on OS different from Windows, NIOFSDirectory implementation used. And SimpleFSDirectory for Windows stations. NativeFSLockFactory is an optimal solution for wide variety of cases including clustered environment with NFS shared resources. But those default can be overridden with the help of system properties. There are two properties: "org.exoplatform.jcr.lucene.store.FSDirectoryLockFactoryClass" and "org.exoplatform.jcr.lucene.FSDirectory.class" that are responsible for changing default behavior. First one defines implementation of abstract Lucene LockFactory class and the second one sets implementation class for FSDirectory instances. For more information please refer to Lucene documentation. But be sure You know what You are changing. JCR allows end users to change implementation classes of Lucene internals, but doesn't guarantee it's stability and functionality.