For non-RLS access, VSAM uses the share options settings to determine the type of sharing permitted. If you set the cross-region share option to 2, a non-RLS open for input is permitted while the data set is already open for RLS access. VSAM provides full read and write integrity for the RLS users, but does not provide read integrity for the non-RLS user. A non-RLS open for output is not permitted when already opened for RLS.
VSAM RLS provides full read and write sharing for multiple users; it does not use share options settings to determine levels of sharing. When an RLS open is requested and the data set is already open for non-RLS input, VSAM does check the cross-region setting. If it is 2, then the RLS open is permitted. The open fails for any other share option or if the data set has been opened for non-RLS output.