VSAM RLS supports access to these types of data sets:

• Key-sequenced data set (KSDS)
• Entry-sequenced data set (ESDS)
• Relative-record data set (RRDS)
• Variable-length relative-record data set cluster (VRRDS)

VSAM RLS also supports access to a data set through an alternate index but does not support opening an alternate index directly in RLS mode. Also, VSAM RLS does not support access through an alternate index to data stored under z/OS UNIX System Services.