MFE zDP: The ECA set code is not being subtasked when there are multiple storage systems to activate for the EMCSNAP batch program.

Summary: MFE zDP: The ECA set code is not being subtasked when there are multiple storage systems to activate for the EMCSNAP batch program. The bug causes the ECA processing not to be subtasked when creating new SNAPSETS. ...

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Symptoms

Poor performance when creating SNAPSETS across multiple storage subsystems

Cause

This is due to an Software bug.

Resolution

Permanent Fix:
  • For Mainframe Enablers 8.5, PTF SN85048 has been developed to correct the issue. It is available to download from Dell Online Support.  

Additional Information

Subtasking the ECA processing means, that when a customer has 5 storage boxes (as an example) within their configuration, a new subtask is created to each storage subsystem. Subsequently MFE software issue the ECA syscalls (ECA SET/ECA CLEAR) to each individual storage subsystem at the same time.
This dramatically reduces the entire ECA window time, and therefore reduces the time that I/O is held for the customer when creating a consistent point in time image of all the devices, on all of the storage subsystems,  in the VDG. Without this functionality, users experiencing this bug will see elongated I/O hold times while creating SNAPSHOTs if their VDG contains multiple storage subsystems. Logically the more storage subsystems the greater the delay in processing with the bug.  

Example of Subtasking for ECA:
  
QCAP8001 SUBTASK_EXECUTION_ECA_SET IORC=00000000 TARGET-UCB@=00000000
QCAP8002 SUBTASK_EXECUTION_ECA_SET IORC=00000000 TARGET-UCB@=00000000
QCAP8003 SUBTASK_EXECUTION_ECA_SET IORC=00000000 TARGET-UCB@=00000000
QCAP8004 SUBTASK_EXECUTION_ECA_SET IORC=00000000 TARGET-UCB@=00000000-000003D9.00000000
QCAP8005 SUBTASK_EXECUTION_ECA_SET IORC=00000000 TARGET-UCB@=00000000-000000C5.0000000F
EMCQCAPL SUBTASK_DETACH_ECA_SET - SLOCK_ECA_SET_TECB=40000000
EMCQCAPL SUBTASK_DETACH_ECA_SET - SLOCK_ECA_SET_TECB=40000000
EMCQCAPL SUBTASK_DETACH_ECA_SET - SLOCK_ECA_SET_TECB=40000000
EMCQCAPL SUBTASK_DETACH_ECA_SET - SLOCK_ECA_SET_TECB=40000000
Note: With the issue you will NOT SEE any notification of SUBTASK for ECA_SET.

Addressing PTF (from PTF cover note):
  
++PTF(SN85048) REWORK(2021277) .                              
++VER(Z038) FMID(SSNP850)                                     
      PRE(                                                    
          SN85047                                             
          )                                                   
   /*                                                         
*-------------------------------------------------------------
* PROBLEM DESCRIPTION(S):                                     
* ------------------------------------------------------------
* PROBLEM FIXED: OPT 588804                                   
* USERS AFFECTED: SnapVX and zDP                              
* PROBLEM DESCRIPTION: ECA set is not being subtasked.        
* DESCRIPTION DETAIL:                                         
*                                                             
* When multiple syms are involved, the ECA set operation      
* is not being subtasked.                                     
*                                                             
* PROBLEM RESOLUTION:                                         
*                                                             
* The logic has been corrected to allow the ECA set process   
* to be subtasked when appropriate.                           
*                                                             
* MODULES: EMCQCAPL                                           
*          ESNAZDPL                                           
*                                                             
* ------------------------------------------------------------

Affected Products

Mainframe Enablers
Article Properties
Article Number: 000193006
Article Type: Solution
Last Modified: 10 Oct 2022
Version:  3
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