XRootD plug-in based solutions for site specific require-ments

XRootD† has been established as a standard for WAN data access in HEP and HENP. Site specific features, like those existing at GSI, have historically been hard to implement with native methods. XRootD allows a custom replacement of basic functionality for native XRootD functions through the use of plug-ins. XRootD clients allow this since version 4.0. In this contribution, our XRootD based developments motivated by the use in the current ALICE Tier 2 Centre at GSI and the upcoming ALICE Analysis Facility will be shown. Among other things, an XRootD redirector plug-in which redirects local clients directly to a shared file system, as well as the needed changes to the XRootD base code, which are publicly available since XRootD version 4.8.0, will be presented. Furthermore, a prototype for an XRootD based disk caching system for opportunistic resources has been developed.