Physical file systems that support multiple concurrent connections for read-only access are called sysplex aware for read-only. The zFS physical file system falls into this category. Such file systems are handled the same as the read/write connections for sysplex aware file systems. The read-only connections are attempted locally for each system in the shared file system group, but if the file system volume is not online to a system, then the system becomes a client to the file system by means of cross-system messaging with the owner.