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II06908: PROBLEMS DETECTED WHEN USING THE TAPE MOUNT MANAGEMENT (TMM) METHODOLOGY

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APAR status

  • Closed as canceled.

Error description

  • .
    Last Updated: 06/30/95             VOLREF                      .
                                                                   .
    .
       This informational APAR addresses known problems in DFSMS   .
    Tape  Mount  Management  (TMM)  methodology.  The  list also   .
    includes problems that have already been fixed.   This  APAR   .
    will be updated as and when problems get resolved.             .
                                                                   .
    ************ Problems that have been RESOLVED **************   .
                                                                   .
    1.  Failure in SMS because of SMS volume count limit of 59     .
        Solution:  Reduce  user  specified  volume  count  to 59   .
        OY40354                                                    .
                                                                   .
    2.  Failure in SMS if the volume  count  is  more  than  the   .
        number of volumes in the selected storage group            .
        Solution: Do not fail allocation OY32669                   .
                                                                   .
    3.  Tape  data  sets  can  get  extended  to  5 volumes as a   .
        default but on DASD this cannot be accomplished  without   .
        a change in JCL                                            .
        Solution: Provide volume count as a Data Class parameter   .
        OY40197                                                    .
                                                                   .
    4.  TRTCH=COMP/NOCOMP clashes with VSAM key values in JFCB     .
        Solution:    Differentiate   between   tape   and   VSAM   .
        allocations. See OY42354                                   .
                                                                   .
    5.  SMF 14/15 record suppression                               .
        Solution: OY33622                                          .
                                                                   .
    6.  Warning   message  if  expiration  date  is  limited  by   .
        Management Class                                           .
        Solution: OY24771                                          .
                                                                   .
    7.  Data class invalid for non-SMS data sets                   .
        Solution: OY30326                                          .
                                                                   .
    8.  ACS cannot recognize UNIT=AFF specified                    .
        Solution:  Pass  'AFF=' as the value for &UNIT See APARs   .
        OY32843 and OY35214                                        .
                                                                   .
    9.  TMM storage groups fill up very fast and need a very big   .
        storage group as data sets redirected to DASD have to be   .
        overallocated  and  cannot  wait   until   DFHSM   space   .
        management cycle                                           .
        Solution:   Partial   Release  on  Close.  See  OY39465,   .
        OY39466, OY39467, OY42757, and OY43095                     .
                                                                   .
    10. Interval migration is required for TMM storage groups      .
        Solution: OY43025, OY43026, OY44496                        .
                                                                   .
    11. Release on close does not work when EXCP is used           .
        Solution: OY48521                                          .
                                                                   .
    12. IMS GSAM errors                                            .
                                                                   .
        a.  Reblocking of GSAM DASD datasets on a HSM MIGRATE or   .
            RECALL results in errors                               .
                                                                   .
        b.  If  GSAM  tape  allocations  are  directed  to DASD,   .
            accessed during IMS  checkpoint,  and  are  migrated   .
            before the restart window, errors can occur            .
                                                                   .
        Solution: OY45560, OY45724                                 .
                                                                   .
    13. IDCAMS DELETE of tape data sets results in an allocation   .
        and  a  mount  and  this  causes  unnecessary delays and   .
        overhead.                                                  .
        Solution: Detect a tape data set and  do  an  uncatalog.   .
        See OY60176                                                .
                                                                   .
    14. Incorrect  volume count is used when RETAIN is specified   .
        and the data class has a default volume count              .
        Solution: OY57741                                          .
                                                                   .
    15. The volume count is lost on migrate/recall                 .
        Solution: OY59536, OY60092                                 .
                                                                   .
    16. Restart fails when checkpointed data sets get migrated.    .
            The following messages may occur:                      .
               MSGIHJ007I   RESTART NOT SUCCESSFUL FOR jobname     .
                            (220) MODULE = IGC0N05B                .
               MSGIHJ009I   ERROR ON ddname                        .
               MSGIEF450I   jobname stepname - ABEND=S13F          .
                            ABEND13F                               .
                                                                   .
        Solution:     OY63624,     OY63625/OW00598,     OY65741,   .
        OY65742/OW00739,        OY64885,        OY64816/OW00735,   .
        OW11824/OW11841, and OW11843/OW11844.                      .
                                                                   .
    17. Restart fails for IMS GSAM data set if they are migrated   .
        Solution: OY64814,  OY64816/OW00735,  OY64885,  OY64892,   .
        OY64893/OW00737 and IMS APARs PN45211, PN45212             .
                                                                   .
    18. When  a  non-specific  tape  intended  GDS allocation is   .
        directed to DASD and is not opened, data loss can  occur   .
        if  the  new  empty  generation  rolls  off  the  oldest   .
        generation. Data integrity problems  can  occur  because   .
        programs  which  expect  valid  data encounter the empty   .
        generation.   Job   failures   can   also   occur    for   .
        non-specific,  non-generation data sets, if the job/step   .
        is rerun.                                                  .
        Solution: OY66484 and OW01827                              .
                                                                   .
    19. IEBGENER fails for concatenated data sets if one or more   .
        of the data sets in the concatenation are left  on  tape   .
        and   the  tape  data  set  is  not  the  first  in  the   .
        concatenation                                              .
        Solution: OY66366/OY66223                                  .
                                                                   .
    20. When using TMM storage groups along with 'spill' storage   .
        groups  (volumes/group  in  QUINEW status), datasets are   .
        allocated to the 'spill' volumes  even  though  the  TMM   .
        volumes have enough space to satisfy the allocation. The   .
        problem  is  caused  by the the dual purpose of the high   .
        threshold value; an SMS allocation threshold and a DFHSM   .
        threshold for interval migration.                          .
        Solution: OY65847/OW00241                                  .
                                                                   .
    21. A TMM DASD dataset is not migrated to L2 storage if it's   .
        migration to L1 storage failed due  to  insufficient  L1   .
        space.                                                     .
        Solution: OY65880/OY65882/OW00419                          .
                                                                   .
    **** Additional problems resolved by SMS 1C0 or MVS 522 ****
    **** For additional details on the specifics of SMS     ****
    **** release 1C0 implementation of VOL=REF processing   ****
    **** see the following manuals:
    **** Implementing System Managed Storage (SC26-3123-03) ****
    **** DFSMSdfp Storage Administration Reference          ****
    ****   (SC26-4920-02)                                   ****
    **** Planning for Installation (SC26-4919-02)           ****
    ************************************************************
    .                                                              .
       Depending  on  unique  JCL coding practices, the problems   .
    listed below may or may not apply to  all  TMM  users.  Many   .
    customers   have   experienced  tape  mount  reductions  and   .
    improved  tape  utilization  without  resolution  to   these   .
    problems.                                                      .
                                                                   .
       This  APAR  will  be  updated  when  there is significant   .
    progress to report on the resolution of these problems.        .
                                                                   .
       The resolution of some of these problems requires complex   .
    design changes in multiple  components  and/or  products.  A   .
    resolution  for  such  problems  may  not be available until   .
    subsequent releases.                                           .
                                                                   .
    1.  VOL=REF and/or UNIT=AFF                                    .
                                                                   .
        a.  Allocation fails when the referencing and referenced   .
            data sets are not directed to the same storage group   .
            as the ACS routines cannot  determine  that  VOL=REF   .
            was specified.                                         .
    RESOLUTION:
    Resolved by DFSMS/MVS 1.3.0. (New values in &ALLVOL and &ANYVOL
         ACS read-only variables.)
                                                                   .
        b.  Allocation fails when a NEW  DD  references  another   .
            NEW  DD  which in turn references an existing MOD or   .
            OLD DD and the first DD is SMS managed.                .
                example: DD1 DISP=OLD                              .
                         DD2 VOL=REF=DD1,DISP=(NEW,CATLG)....      .
                         DD3 VOL=REF=DD2,DISP=(NEW,CATLG)....      .
                                                                   .
    RESOLUTION:
    Resolved by DFSMS/MVS 1.3.0. (Resolution of reference deferred
    until locates are done for mod/old data sets.)
        c.  VOL=REF not specified and UNIT=AFF specified. If the   .
            referenced data set is directed to DASD and a NEW or   .
            MOD treated as  NEW  referencing  data  set  is  not   .
            redirected to DASD then Allocation or JES3 fails the   .
            referencing data set allocation.                       .
    RESOLUTION:
    Resolved by MVS/SP 5.2.2 (or OS/390) and up-level JES3. (Allows
    UNIT=AFF to point to DASD when data set is on DASD due to being
    placed there by SMS.)
                                                                   .
        d.  Allocation  for  the referencing data set fails if a   .
            data class was not  derived  by  the  ACS  routines,   .
            since  space  is usually not specified for tape data   .
            sets.                                                  .
    ***** Also, take care when using LIKE= for DS's to be
          TMM'ed. If the ds being LIKED to is a model DSCB
          originally allocated with SPACE=(0,n) then this
          space value will be derived via LIKE=. LIKE=
          overrides over rides any space value assigned via
          dataclas. With space = 0 the allocation may fail
          with a JCL error and msgigd17045i "SPACE not
          Specified.....".
          To get around this problem re- allocate the model
          DSCB with a "real" space value, adequate to accomodate
          the largest of the ds's which will LIKE= to it. If
          "wasted" dasd space is a problem then use PARTIAL
          RELEASE in an SMS assigned MGMTCLAS management class
          to release over allocated space when the ds is closed.
    RESOLUTION:
    Resolved by DFSMS/MVS 1.3.0. (Data class processing was moved so
    that it is now handled with VOL=REF processing.
                                                                   .
        e.  Allocation fails when all of  the  referencing  data   .
            sets  are not directed to SMS DASD using VOL=REF and   .
            the referenced data set was directed to DASD.          .
                                                                   .
    LIMITED RESOLUTION:
    This is still true for VOL=REF since it is one way of implying
    stacking. IBM intends no change to allow data sets using
    VOL=REF to be directed to different media. This would cause
    other problems. However, additional information is provided
    via &ALLVOL and &ANYVOL read-only variables so that construct
    assigned can be directed consistently.
    .
        f.  Using VOL=REF with SMS managed data sets forces  the   .
            referencing  data  set  to  be allocated in the same   .
            storage group as the referenced data set.  This  can   .
            cause  large  data sets to be allocated in the small   .
            data set pool.                                         .
                                                                   .
            The following messages may occur with the above        .
            problems:                                              .
               MSGIEF475I   VOL ON INELIGIBLE PERMRES OR RESERVED  .
                            DEVICE                                 .
               MSGIEF318I   UNIT=AFF INVALID FOR REQUEST SPECIFYING.
                            NEW DIRECT ACCESS DATA SET             .
               MSGIAT4301   UNIT TYPE PARAMETER FOR STEPNAME IS NOT.
                            VALID - JOB FAILED                     .
               MSGIGD17045I SPACE NOT SPECIFIED FOR ALLOCATION OF  .
                            DATA SET                               .
                                                                   .
    
    
    Resolved by DFSMS/MVS 1.3.0. (For ATL, the data sets still need
    to go in the same storage group. This is because they must go on
    the same tape and a tape can be in only one storage group. For
    DASD, another storage group can be assigned as long as it is of
    compatible type (POOL or VIO). )
    .
                                                                   .
        g.  All   datasets   which  meet  criteria  outlined  in   .
            Allocation APAR OY66484 which  are  not  opened  are   .
            deleted at step termination.  MSGIGD105I is received   .
            indicating   the   deletion  of  the  DASD  dataset.   .
            Applications which have been altered to recognize  a   .
            TMM  redirected  dataset as being a DASD dataset may   .
            fail if the DASD dataset is deleted.                   .
                                                                   .
            See APAR OW08887                                       .
                                                                   .
    

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

  • Informational APAR only
    

APAR Information

  • APAR number

    II06908

  • Reported component name

    V2 LIB INFO ITE

  • Reported component ID

    INFOV2LIB

  • Reported release

    001

  • Status

    CLOSED CAN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    1993-04-20

  • Closed date

    1993-04-20

  • Last modified date

    1996-10-29

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

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

Fix information

Applicable component levels

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Document Information

Modified date:
13 December 2020