Sharing VSAM files through RLS

By using the VSAM JCL parameter RLS, you can specify record-level sharing with VSAM. Specifying RLS is the only way to request the RLS mode when running COBOL programs.

Use RLS=CR when consistent read protocols are required, and RLS=NRI when no read integrity protocols are required. You cannot specify RLS if you allocate your VSAM data set with an environment variable

Related references  
Restrictions when using RLS