OA47796: NEW FUNCTION - SUPPORT FOR SYSTEM-MANAGED ASYNCHRONOUS DUPLEXING FOR LOCK STRUCTURES

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Installations exploiting parallel sysplex at *
  *                 z/OS V2R2 (HBB77A0) using coupling facility  *
  *                 (CF) lock structures for data and            *
  *                 transaction serialization, and desiring to   *
  *                 duplex those structures for increased        *
  *                 reliability, particularly at distance.       *
  *                                                              *
  *                 SYSPLEXDS                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: New function: Introduce an asynchronous *
  *                      system-managed duplexing protocol for   *
  *                      improved duplexing performance.         *
  ****************************************************************
  * RECOMMENDATION: This PTF will not be effective on the system *
  *                 to which it is being applied until the PTF   *
  *                 for this APAR is applied to all systems in   *
  *                 the sysplex.  An IPL is required to activate *
  *                 this fix on each system of the sysplex,      *
  *                 however a rolling IPL is sufficient to       *
  *                 activate the fix.                            *
  ****************************************************************
  Synchronous system-managed duplexing requires that both
  primary and secondary CFs execute structure-modifying
  operations in a coordinated manner.  Both primary and
  secondary operations must complete and be evaluated
  for consistency before the system can return the results
  of a request to the exploiting application.  For highly
  performance-sensitive operations such as serialization
  requests directed to lock structures, the performance
  cost associated with system-managed duplexing may be
  prohibitive.  This is particularly problematic when the
  primary and secondary CFs are a long distance apart.
  New function is required to reduce this performance cost.
  

Problem conclusion

Temporary fix

Comments

• Asynchronous system-managed duplexing for lock structures
  provides performance characteristics nearly equivalent to those
  of simplex operations while still providing the enhanced
  reliability of a duplexed structure.  In this protocol, the
  primary CF is responsible for forwarding updates to the
  secondary CF, and the secondary CF applies those updates
  asynchronously with respect to the original exploiter request.
  This has the following implications:
  
  o Since the primary and secondary CFs no longer need to execute
    commands in a synchronized manner, the results of a request
    can be returned to the exploiter as soon as the associated
    command(s) complete at the primary CF.  Thus, request service
    times approximate simplex service times.
  
  o Because the secondary CF processes commands asynchronously,
    the secondary structure instance will nearly always lag the
    primary instance.  That is, the secondary instance will
    not necessarily contain updates associated with requests for
    which completion has already been reported to the exploiter.
    This imposes new requirements on the system and exploiting
    applications:
  
    o The primary CF assigns a unique, monotonically-increasing
      sequence number to every operation that updates the
      structure.  If an asynchronously-duplexed structure must
      fail over to begin using the secondary structure instance
      (rebuild switch), z/OS uses those sequence numbers to
      propagate to the surviving (former secondary) structure
      instance any updates it may be missing.
  
    o Locking applications using the record data feature of lock
      structures:
  
      o Applications must track the sequence numbers associated
        with requests and correlate them with in-flight
        transactions.  z/OS returns the sequence numbers to
        exploiters through updated IXLLOCK, IXLYCMPL, IXLYNEPL,
        IXLYLRB, and IXLYRTAA interfaces.
  
      o When an application wishes to commit a transaction, it
        must exploit the new IXLADUPX interface to verify that
        any associated structure updates have been propagated to
        the secondary structure instance.
  
      o Application connectors must indicate their ability to
        participate in the asynchronous duplexing protocol by
        specifying the new IXLCONN ASYNCDUPLEX keyword.
  
    o Locking applications that do not use record data do not
      require any updates to exploit asynchronous duplexing
      beyond the existing requirements for supporting any
      system-managed process.
  
  To exploit asynchronous system-managed duplexing, all systems in
  the sysplex must be at a release / service level equal to or
  higher than z/OS V2R2 (HBB77A0) with PTFs for OA47796, and must
  be running with a CFRM couple data set formatted to support
  asynchronous duplexing (ITEM NAME(ASYNCDUPLEX) NUMBER(1)).
  
  Publication updates associated with this APAR can be found at
  http://publibz.boulder.ibm.com/zoslib/pdf/OA47796.pdf.
  Summary of updates:
  
  z/OS MVS Programming: Sysplex Services Guide (SA23-1400)
  --------------------------------------------------------
  o IXCQUERY feature description
  o Connector considerations for asynchronous duplexing
  o Structure rebuild processing
  o Working with asynchronously-duplexed structures
  o Using lock services with asynchronously-duplexed structures
  o Using the new IXLADUPX interface
  o Accounting and measurement updates
  
  
  z/OS MVS Programming: Sysplex Services Reference (SA38-0658)
  ------------------------------------------------------------
  o IXLADUPX (new API)
  o IXLCONN
  o IXLCSP
  o IXLLOCK
  o IXLMG
  o IXLREBLD
  o IXLRT
  o IXLSYNCH
  
  
  z/OS MVS Setting Up a Sysplex (SA23-1399)
  -----------------------------------------
  o Description of asynchronous duplexing and comparison with
      synchronous duplexing
  o Migration steps for asynchronous duplexing
  o Formatting a CFRM couple data set for asynchronous duplexing
    (IXCL1DSU)
  o Defining a CFRM policy for asynchronous duplexing (IXCMIAPU)
  
  
  z/OS MVS System Messages Vol. 10 (SA38-0677)
  --------------------------------------------
  o IXC347I
  o IXC358I
  o IXC359I
  o IXC360I
  o IXC367I
  o IXC522I
  o IXC528I
  o IXC531I
  o IXC538I
  o IXC544I
  o IXC546I
  o IXC571I
  o IXC574I
  o IXC577I
  o IXC584I
  o IXC745I
  o IXCH0210E
  o IXCH0211I
  o IXCH0920I
  o IXL001W
  o IXL020I
  o IXL023I
  o IXL150I
  
  
  z/OS V2R2 MVS Data Areas Vol. 3 (GA32-0937)
  -------------------------------------------
  o IXCYQUAA
  o IXLYAMDA
  o IXLYCMPL
  o IXLYCON
  o IXLYCONA
  o IXLYEEPL
  o IXLYLRB
  o IXLYNEPL
  o IXLYRTAA
  
  
  z/OS MVS System Codes (SA38-0665)
  ---------------------------------
  o New ABEND026 reason codes
  
  
  IBM Health Checker for z/OS V2R2 User's Guide (SC23-6843)
  ---------------------------------------------------------
  O Update discussion of check (IBMXCF,XCF_CF_STR_DUPLEX).
  ×**** PE17/01/30 FIX IN ERROR. SEE APAR OA52015  FOR DESCRIPTION
  ×**** PE17/01/19 FIX IN ERROR. SEE APAR OA51945  FOR DESCRIPTION
  ×**** PE17/10/18 FIX IN ERROR. SEE APAR OA54179  FOR DESCRIPTION
  ×**** PE17/10/16 FIX IN ERROR. SEE APAR OA54179  FOR DESCRIPTION
  ×**** PE18/04/16 FIX IN ERROR. SEE APAR OA55172  FOR DESCRIPTION
  ×**** PE18/03/26 FIX IN ERROR. SEE APAR OA55172  FOR DESCRIPTION
  ×**** PE19/01/09 FIX IN ERROR. SEE APAR OA56539  FOR DESCRIPTION
  ×**** PE19/01/09 FIX IN ERROR. SEE APAR OA56539  FOR DESCRIPTION
  ×**** PE19/01/14 FIX IN ERROR. SEE APAR OA56539  FOR DESCRIPTION
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UA82981 UA82982

Modules/Macros

• BLSABDPL IXCCFRMF IXCF1TUX IXCF1TX2 IXCHCADC IXCHCMST IXCHCSTR
  IXCI2PH1 IXCL2AAT IXCL2ACE IXCL2ALR IXCL2ALT IXCL2ASR IXCL2ATC
  IXCL2ATH IXCL2BAP IXCL2BLD IXCL2CLT IXCL2EVT IXCL2FDD IXCL2FDF
  IXCL2FDP IXCL2FOR IXCL2GAT IXCL2MON IXCL2NIP IXCL2PCT IXCL2QRY
  IXCL2RAT IXCL2RC  IXCL2RHT IXCL2RSR IXCL2SCC IXCL2SCL IXCM2MST
  IXCM2MS3 IXCO1DC3 IXCXCFEN IXCXCFJP IXCXCHEN IXCXCHJP IXCYQUAA
  IXLADUPX IXLA1MG  IXLA1SLM IXLCONN  IXLCSP   IXLC1CON IXLC1CSP
  IXLC1DCN IXLC1EOT IXLC2INT IXLC2LBF IXLC2LIN IXLC2OPC IXLC2RCD
  IXLC3ASC IXLC3CRF IXLC3DPR IXLC3DSC IXLC3LTN IXLC3SCN IXLD2GLC
  IXLE1MEV IXLE1RCV IXLE1RDV IXLE1REC IXLE1RTY IXLF1ACC IXLF1ARQ
  IXLF1ASD IXLF1AS2 IXLF1AS3 IXLF1CBF IXLF1CON IXLF1CVT IXLF1DEL
  IXLF1EXE IXLF1FAT IXLF1FAX IXLF1LKM IXLF1MON IXLF1NAM IXLF1RES
  IXLF1RTR IXLF1SFP IXLF1SIG IXLF1SI2 IXLF1STK IXLF1TFT IXLF1TF1
  IXLF1TF2 IXLF1TF4 IXLF1TF5 IXLF1TF6 IXLF1TRC IXLF1TUX IXLF1TX2
  IXLF1VAW IXLF1VCL IXLF1VCN IXLF1VMA IXLF1VME IXLF1VMT IXLF1VRC
  IXLF1VSL IXLF1VST IXLF1VSU IXLF1XES IXLF1XPR IXLIXLEN IXLIXLJP
  IXLI1LPX IXLI1SIN IXLLIST  IXLLOCK  IXLLSTE  IXLMG    IXLM1DMP
  IXLM1MST IXLM1MS2 IXLM1REC IXLM1RMT IXLM1TBL IXLM1TB2 IXLM1TMR
  IXLM2CR  IXLM2DIE IXLM2DR  IXLM2DRL IXLM2DRR IXLM2DRS IXLM2DSP
  IXLM2LRS IXLM2MR  IXLM2SG  IXLM2SP  IXLM2SR  IXLM2XRQ IXLM2XSR
  IXLREBLD IXLRT    IXLR1ADS IXLR1ALR IXLR1ALT IXLR1BUN IXLR1CAC
  IXLR1CMP IXLR1CRR IXLR1DES IXLR1DIA IXLR1GLB IXLR1GLC IXLR1GRN
  IXLR1GRT IXLR1LCK IXLR1LCR IXLR1LKR IXLR1LPT IXLR1LRR IXLR1LRS
  IXLR1LST IXLR1NEI IXLR1NLA IXLR1PAL IXLR1QRY IXLR1RCK IXLR1RCS
  IXLR1RES IXLR1RRE IXLR1RRS IXLR1RSM IXLR1RSU IXLR1RT  IXLR1SIG
  IXLR1SRB IXLR1SUS IXLR1SYN IXLR1UNL IXLR2CHS IXLR2LSF IXLR2MAN
  IXLR2MPR IXLR2PLA IXLR2QUE IXLR2SSD IXLR2SSF IXLR3DFS IXLR3DSF
  IXLSYNCH IXLS1REC IXLS1RNP IXLX1AEI IXLX1ASO IXLX1ASR IXLX1CNF
  IXLX1CNP IXLX1EER IXLX1RES IXLYAMDA IXLYCMPL IXLYCON  IXLYCONA
  IXLYEEPL IXLYLRB  IXLYNEPL IXLYRTAA
  

Fix information

• Fixed component name

  CROSS SYS.EXT.S

• Fixed component ID

  5752SCIXL

Applicable component levels

• R7AJ PSY UA82982

     UP16/10/25 P F610

• R7A0 PSY UA82981

     UP16/10/25 P F610

Fix is available

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