MFE SRDF-HC: The R22SWTCH command completed with a RC=0 when no eligible devices were found.

The customer was performing an unplanned DR test running GDDR script GDDRUP31 in a STAR with AutoSwap environment.

During the execution of the script, one of the steps is to issue a SRDF-HC R22SWTCH command using the dynamic REXX API to unblock the DC1-DC3 recovery leg to allow a RDF-RSUM command to be issued. This completed with a RC=0.
 

+GDDR721I GDDR Starting Issue RDF command R22S (Internal) with sites DC3 and DC2                                      
+GDDR721I GDDR Starting Submit GDDR function to remote C system for command GDDRRDF0 at Site DC3                      
+GDDR Completed Submit GDDR function to remote C system with rc 0                                            
+GDDR721I GDDR Starting Script Function Call Stats                                                                    
+GDDR639I GDDR Function Status ===> 691                                                                              
   691              >                                                                                                                    
   691              > GDDR Function Issue RDF Command ( GDDRRDF0 )                                                                       
   691              >      Completed step 36 of xx in 63.94401 Seconds                                                                   
   691              >      With Return code 0                                                                                            
   691              >  

From the GDDRWORK started task.

GDDR721I GDDR Starting Issue RDF Command (R22S) for sites DC3 and DC2 (STAR)                           
GDDR705I GDDR Rerun state checker has initialized GLOBAL.GDDR.RUN.GDDRUP31.GDDRRDF0_R22S_DC3_DC2_I_1.RC
GDDR705I GDDR Rerun state checker has initialized                   GLOBAL.GDDR.RUN.GDDRUP31.GDDRRDF0_D32_R22S_I_1_1.RC  
GDDR671W GDDR Loading R22S command 1 of xx                                                             
GDDR001I GDDR .... SC VOL,LCL(gkpr,Ragrp),R22SWTCH,xxxx-yyyy                                
GDDR721I GDDR Starting Call DYNAPI Interface to enqueue commands                                       
GDDR705I GDDR Rerun state checker has initialized                                                                                                                  
GDDR639I GDDR Completed Issue RDF Command (R22S) with rc 0 

The subsequent step to issue the RDF-RSUM command failed with a EMCCM73E/EMCCW56E message because there were no eligible devices because the devices were still linked blocked, indicating that the R22SWTCH command had not worked correctly but gave a RC=0. 
 

From the SYSLOG
 

EMCCM73E R2 of pair blocked, recovery procedures are required.                                    
EMCCW56E No eligible devices found  

When a REXX function 19 (Dynamic RDF) call is issued and no devices requested are eligible, the REXX interface returns a return code of 0. This behavior is inconsistent with REXX function 02 (Legacy API) and Host Component processing of the identical command, which returns a return code of 8.                                

• For Mainframe Enablers 10.0.0, PTF SRA0005 has been developed to correct the issue. It is available to download from Dell Technologies Online Support.
• For Mainframe Enablers 8.5, PTF SR85038 has been developed to correct the issue. It is available to download from Dell Technologies Online Support.