OA49548: NEW FUNCTION

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function.
  
  Important: If preparing to install this new function, it is
  recommended to install OA47115, OA49548, OA51983, and OA52305
  together.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of Extended Remote Copy (XRC).     *
  ****************************************************************
  * PROBLEM DESCRIPTION: XRC buffer constraints limit XRC        *
  *                      resiliency after impact to throughput   *
  *                      from workload skew or write             *
  *                      performance issues.                     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

Temporary fix

Comments

• New function: the maximum number of buffers for XRC has been
  increased.
  
  The following updates will be reflected in a future revision
  of z/OS MVS System Messages, Volume 1(ABA-AOM)(SA38-0668):
  
  ANTB8009W XRC SESSION(session_id) JOURNAL DATA SETS NOT
  EXTENDED FORMAT SEQUENTIAL. TOTALBUFFERS(total_bufs) LIMITED
  TO 25000
    Explanation: The data set organization of the journal data
      sets does not allow XRC data buffers to reside above the
      2GB storage bar.  The TOTALBUFFERS value specified in the
      PARMLIB, total_bufs, is limited to 25000.
    Source: Extended Remote Copy (XRC)
    System Action: XRC functions are active.
    System Programmer Response: To take advantage of the large
      number of XRC data buffers that are available, journal
      data sets must all be allocated as extended format
      sequential. See section entitled "Specifying XRC
      journal, control, and state data sets" in Chapter
      "Setting up the extended remote copy environment" of the
      DFSMS Advanced Copy Services manual. This shows
      instructions on how to allocate extended format sequential
      journal data sets, and copy data from the old format
      journal data sets to the new extended format sequential
      journal data sets.
  
  
  The following updates will be reflected in a future
  revision of z/OS DFSMS Advanced Copy Services (SC23-6847).
  
  The topic entitled "Real Storage Requirements" in chapter 3,
  "Planning for extended remote copy," is changed.
  
  The third and fifth paragraphs are updated as follows.
  
  Data movement buffers are 60K bytes. The number of buffers
  is controlled by PARMLIB value BuffersPerStorageControl,
  multiplied by the number of readers, with an overall limit
  imposed by the TotalBuffers PARMLIB value.
  A fully-configured session will have 300,000 buffers, which
  requires approximately 18,100MB (18.1GB) of real storage to
  page fix. The buffers are fixed and freed as the session
  requires. Peak buffer demand for a session may not occur
  for several hours, or even days after the session
  is started.
  
  Each data mover may use up to an additional 100MB of real
  storage above that required for data movement buffers.
  This makes a total real storage requirement of
  18,100MB (18.1GM) per fully-configured XRC session.
  
  
  The topic entitled "Specifying the journal data sets" in
  Chapter 4, "Setting up the extended remote copy
  environment", is changed.
  
  In the list of recommended specifications, the following
  bullet is added after "Define the journal data sets as
  striped SAM data sets" and before "Make journal data
  sets large enough...":
  -If the journal data sets are not defined as striped SAM data
   sets, the following conditions are in effect:
    - At XSTART time, message ANTB8009W is displayed.
    - Buffers are not eligible for allocation above the 2GB
      bar.
    - TotalBuffers cannot exceed 25,000.
  
  In the same section, the note is changed as follows.
  
  Note: To maximize performance and avoid stall conditions,
  use the following to determine the size of each
  journal data set.
  
  1. No journal should be allocated smaller than the largest
  possible consistency group, which is 1300 * the number of
  readers in the session, but cannot exceed 4/3 * the maximum
  buffers in the session.  For example, with 32 readers, each
  journal should have a primary allocation of 41,600 tracks,
  or 4/3 the TotalBuffers value if that is smaller.
  
  2. The total of all journal allocations should be greater
  than 4/3 the maximum XRC buffers tracks. For example, with
  TotalBuffers and BuffersPerStorageControl set to 300,000 the
  total of all journal allocations must be 400,000 tracks.
  With 8 journals, each journal must be 50,000 tracks.
  With 16 journals, each journal must be 25,000 tracks, but
  should not be smaller than the consistency group size of
  41,600 tracks.
  
  
  In the table "ANTXIN00 parmlib parameters" from Chapter 6
  "Administering your extended remote copy environment",
  make the following changes:
  BuffersPerStorageControl  range from 100-25000 to 100-999999
  TotalBuffers  range from 100-25000 to 100-999999
  PermanentFixedPages  range from 0-9999 to 0-99999
  
  
  Update the detailed descriptions of the parmlib values as
  follows.
  
  BuffersPerStorageControl
  Specifies how many buffers XRC allocates per reader
  specified. A value of 576 allocates 35 MB per unique reader
  specified with the XADDPAIR command. Some customers have
  modified this field to a higher number to use the maximum
  number of buffers, even with a small number of sessions. You
  can specify a value between 100 and 999999 buffers.
  
  TotalBuffers
  Controls the maximum number of buffers used for an XRC session.
  Some customers have used a lower value to limit the amount of
  real storage that is used for an XRC session. You can specify
  a value between 100 and 999999 buffers.  It is recommended
  that a value of 300000 or less is used.  If the journal
  datasets used in the XRC session are not extended format,
  the TotalBuffers value will be limited to 25000.
  
  PermanentFixedPages (PAGEFIX)
  Specifies the maximum amount of real storage, in MB, that XRC
  keeps page fixed to process I/O operations. You can specify a
  value between 0 and 99999 MB. A value of 0 directs XRC to
  release fixed pages after they have been used.
   KEYWORDS: XRC/K
  ×**** PE17/02/02 FIX IN ERROR. SEE APAR OA51983  FOR DESCRIPTION
  

APAR Information

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

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

  OA49555 UA83392 UA83393

Modules/Macros

• ANTBUFER ANTCLEAN ANTCLEN2 ANTCTFIL ANTCTFMT
  ANTEDIEL ANTIO    ANTIOPGS ANTRCB2  ANTRCX2  ANTS4013 ANTS4017
  ANTS4019 ANTS4022 ANTS4030 ANTS4031 ANTS4034 ANTS4041 ANTS4042
  ANTS4043 ANTS4044 ANTS4063 ANTS4071 ANTS4073 ANTS4101 ANTS4102
  ANTS4150 ANTS4151 ANTS4153 ANTS4158 ANTS4159 ANTS4912 ANTS4928
  ANTS4935 ANTS5000 ANTS5001 ANTS5002 ANTS5003 ANTS5004 ANTS5005
  ANTS5006 ANTS5007 ANTS5008 ANTS5009 ANTS5010 ANTS5011 ANTS5012
  ANTS5013 ANTS5014 ANTS5015 ANTS5017 ANTS5018 ANTS5019 ANTS5020
  ANTS5021 ANTS5022 ANTS5023 ANTS5024 ANTS5025 ANTS5026 ANTS5027
  ANTS5028 ANTS5030 ANTS5031 ANTS5032 ANTS5033 ANTS5034 ANTS5035
  ANTS5036 ANTS5037 ANTS5055 ANTUFREA ANTUFWRI ANTUGDVC ANTUHAUL
  ANTXALAN ANTXA00B ANTXA00C ANTXA00D ANTXA00F ANTXA000 ANTXA100
  ANTXBFRN ANTXBOB  ANTXCGC  ANTXCGF  ANTXCGF2 ANTXCGF3 ANTXCLIP
  ANTXCLMX ANTXCOM2 ANTXCOM3 ANTXCOM4 ANTXCOM5 ANTXCOM6 ANTXCOM7
  ANTXCOM8 ANTXCROK ANTXCRSM ANTXCSTR ANTXC00G ANTXC100 ANTXDITY
  ANTXEATR ANTXESD  ANTXHEIN ANTXHERD ANTXHERO ANTXIOLG ANTXJCWM
  ANTXJNTR ANTXJRCD ANTXJRCF ANTXJRCG ANTXJRIN ANTXJRMM ANTXJRSF
  ANTXJRTT ANTXJTIN ANTXJTI5 ANTXJTRM ANTXJTSK ANTXJWBM ANTXJWCF
  ANTXJWMM ANTXJWSF ANTXJWTT ANTXKHNG ANTXPRSM ANTXRONK ANTXROTO
  ANTXRSAN ANTXRSMG ANTXRSSE ANTXRUTR ANTXSMID ANTXSOCL ANTXTUNI
  ANTXTUN1 ANTXTUN2 ANTXTUN3 HDZ2210J HDZ2220J
  

Fix information

• Fixed component name

  SYSTEM DATA MOV

• Fixed component ID

  5695DF117

Applicable component levels

• R210 PSY UA83392

     UP16/12/13 P F612

• R220 PSY UA83393

     UP16/12/13 P F612

Fix is available

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