SAS(R) 9.1.3 Companion for z/OS

Using SAS Data Libraries Using Multivolume SAS Data Libraries 63
volume until 16 extents have been allocated for the data set on that volume, or the
volume does not contain enough free space to satisfy the request. If the space request
cannot be satisfied, the system will attempt to find space on the next volume, if any,
that is allocated to the library data set. If no additional volumes are allocated to the
data set, the system will issue a system B37 abend, which SAS intercepts and reports
as a library full condition.
Requesting Space As Needed
These examples show how to request space as needed for SAS direct access bound
data libraries.
The following LIBNAME statement allocates a temporary library of up to three
volumes:
libname tmp ’&lib’ unit=(sysda,3) space=(cyl,(300,100));
The following DD statement creates a direct access bound library. The unit count
makes three volumes to be available for the job that creates the library. Note that there
must be three available units in the system for this example to work, even if the data
library does not require space on all three volumes, because the system chooses the
candidate volumes at allocation time.
//WORK DD DSN=MY.MASTER.LIBRARY,DISP=(NEW,CATLG,DELETE),
// UNIT=(DISK,3),SPACE=(CYL,(300,100))
To extend this library to as many as five volumes using another job, the following DD
statement could be used. The secondary space allocation specified at library creation
time is used to determine the size of the secondary extents added.
//WORK DD DSN=MY.MASTER.LIBRARY,DISP=OLD,UNIT=(DISK,5)
If you want to extend an existing library, but only on the volumes that it already
occupies, it is not necessary to specify the UNIT parameter.
As shown below, it is also possible extend an existing library (not SMS-managed) via
the LIBNAME statement EXTEND option, which is equivalent to specifying UNIT=(,n),
where n is one more than the current number of volumes in the existing library:
libname payroll ’my.master.library’ disp=old extend;
The following DD statement creates an SMS-managed data library, which can extend
to as many as four volumes. For SMS-managed libraries allocated without an explicit
list of volumes, the unit count specified when creating the library, specifies the volume
count for the library data set. Note that the volume count can also be specified via the
data class instead of the unit count.
//TEST1 DD DSN=MY.PROJECT.LIBRARY,DISP=(NEW,CATLG),
// UNIT=(DISK,4),SPACE=(CYL,(200,200)),
// STORCLAS=SASSTD,DATACLAS=SASSTD,DCB=(DSORG=PS,RECFM=FS)
The volume count represents the maximum number of volumes to which the data set
can be extended in creating jobs as well as in subsequent jobs. Therefore, this library
could be extended to as many as four volumes using the following DD statement:
//TEST1 DD DSN=MY.PROJECT.LIBRARY,DISP=OLD
The following LIBNAME statement could be used as well:
libname project ’my.project.library’;
Extending an existing SMS-managed library does not require a UNIT count, nor does
it have any effect. To increase the volume count for an existing SMS-managed library,
use the ADDVOL command of the IDCAMS utility.