z/OS DFSMSdss Storage Administration
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VOLCOUNT

z/OS DFSMSdss Storage Administration
SC23-6868-01

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   .-VOLcount(*)---------------------.   
>>-+---------------------------------+-------------------------><
   '-VOLcount--(--+-SRC---------+--)-'   
                  +-N--(--nn--)-+        
                  '-ANY---------'        

VOLCOUNT specifies the method DFSMSdss uses to determine the number of volumes (volume count) for allocating the SMS target data set for a logical data set restore of VSAM or non-VSAM data sets.
* (asterisk)
Specifies that DFSMSdss determine the volume count for allocation according to the following conditions:
  • If the source data set is a single-volume data set, one volume is allocated.
  • If the source data set is a multivolume data set and either a list of volumes is not specified to DFSMSdss through OUTDDNAME or OUTDYNAM or there are no SMS volumes in the list, DFSMSdss allocates the same number of volumes that were in the multivolume source data set.
  • If the source data set is a multivolume data set and a volume list is specified through OUTDDNAME or OUTDYNAM, the volume count is the number of SMS volumes in the list.

DFSMSdss does not adjust the final number of candidate volumes after the allocation is complete.

The * (asterisk) is the default for this keyword.

SRC
Specifies that DFSMSdss rely on the source volume count to determine the number of volumes to allocate for the target data set as follows:
  • If no output volume list is specified, DFSMSdss allocates the same number of volumes that the source data set had.
  • If a volume list is specified through OUTDDNAME or OUTDYNAM, the volumes in the list that are SMS-managed must be in the same storage group, and the allocation must be directed to that storage group.

DFSMSdss does not adjust the final number of candidate volumes after the allocation is complete.

N(nn)
nn represents the number of volumes to be used for SMS data set allocation. Any value between 0 and 59 can be specified with the following conditions:
  • If nn is not zero and a volume list is specified through OUTDDNAME or OUTDYNAM, DFSMSdss allocates either the number of SMS volumes in the volume list or nn, whichever is less.
  • If nn is zero and a volume list is specified through OUTDDNAME or OUTDYNAM, DFSMSdss allocates either the number of SMS volumes in the volume list or the number of volumes that were allocated for the source data set, whichever is less.
  • If a volume list is specified through OUTDDNAME or OUTDYNAM and there are no SMS volumes in the list, or there is no volume list, DFSMSdss allocates either the number of volumes used by the source data set or nn, whichever is more.

DFSMSdss does not adjust the final number of candidate volumes after the allocation is complete.

ANY
Specifies that DFSMSdss use a maximum volume count to allocate the SMS target data set as follows:
  • DFSMSdss initially sets a volume count of 59 for the allocation.
  • If the data set is allocated on more volumes than were used to allocate the source data set, DFSMSdss reduces the number of volumes used to the number of primary volumes needed to satisfy the allocation.
  • If the data set is allocated on the same number or fewer volumes than were used to allocate the source data set, DFSMSdss reduces the number of volumes used to the number of volumes used for allocation of the source data set.
Note:
  1. VOLCOUNT does not convert any of the following data sets to multivolume: PDS or PDSE data sets, single-volume data sets whose organization is undefined, or empty non-VSAM, single-volume data sets.
  2. VOLCOUNT does not change the number of volumes for key-range KSDS data sets.
  3. Guaranteed space is not honored when VOLCOUNT(ANY) is used.
  4. VOLCOUNT(ANY) does not support keyed VSAM data sets that have an imbedded index. If VOLCOUNT(ANY) is specified and a data set has an imbedded index, the data set is processed as if VOLCOUNT(*) were specified.
  5. VOLCOUNT(ANY) does not support any type of striped data set (physical, sequential, extended, or VSAM). If VOLCOUNT(ANY) is specified and a data set is striped, the data set is processed as if VOLCOUNT(*) were specified.
  6. When you specify VOLCOUNT(ANY), the &ANYVOL and &ALLVOL read-only variables are not available to the storage group ACS routine.
  7. For nonguaranteed-space, striped VSAM data sets: The minimum number of volumes that DFSMSdss allocates is determined by the number of stripes, which is based on the STORCLAS sustained data rate (SDR). DFSMSdss does not consider the number of volumes in the output volume list, or any of the VOLCOUNT specifications. If there are not enough enabled volumes in the STORGRP to support the SDR, DFSMSdss reduces the number of stripes. If there are excess volumes specified, those volumes become nonspecific (*) candidates.
  8. For guaranteed-space, striped VSAM data sets: DFSMSdss allocates the number of volumes that are specified in the output list, regardless of the SDR. (To be striped, the SDR must be greater than zero.) The VOLCOUNT rules described above apply.

You can override VOLCOUNT keyword settings with the options installation exit routine, as described in z/OS DFSMS Installation Exits.

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