Not just NFS, but most shared file systems including SMB do not have a proper notion of file locks (perhaps RHAT's GFS may be different). And Galder is right, FCL is not performant for large trees since this involves directory traversal, but then again I'm sure this depends on the file system used (ext3 vs reiserfs vs Windows NTFS, etc). To be honest, I tend to recommend not using this at all in production. I think a much better bet would be the JDBM cache loader, which is pretty poorly documented at the moment. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3978798#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...