Use these save methods to decrease your save window by saving to multiple devices.
Set up saves to multiple devices
You can reduce your save window by using multiple devices. When you save to multiple devices you can use one of two techniques. You can issue a single save operation as one job, or you can issue multiple save operations as several jobs.
Single save operation
Save (or restore) operations identify a media file by the device (DEV), sequence number (SEQNBR), volume identifiers (VOL), and file label (LABEL) parameters. These parameters only allow one media file to be identified. However, a parallel save (or restore) operation uses more than one media file. You can solve this problem by using a media definition.
A media definition (*MEDDFN) allows
you to identify more than one media file. A media definition defines the devices,
sequence numbers, and volume identifiers that the parallel save operation
will use. 
A media definition also allows
you to specify whether to save the data in parallel or serial format and whether
to use dynamic device allocation.
You create a media definition
by using the Create Media Definition (QsrCreateMediaDefinition (ILE) or QSRCRTMD
(OPM)) API.
Multiple save operation
When you issue multiple save operations to save different sets of data to different media devices, you perform concurrent saves. The following scenarios provide some examples of situations when you may want to perform concurrent saves within the Integrated File System.
- Save the complete Integrated File System structure and all user libraries
concurrently:
SAV DEV('/QSYS.LIB/TAP01.DEVD') OBJ(('/*') ('/QSYS.LIB' *OMIT) ('/QDLS' *OMIT)) SAVLIB LIB(*ALLUSR) DEV(TAP02) - Save separate unmounted user-defined file systems concurrently:
SAV DEV('/QSYS.LIB/TAP01.DEVD') OBJ(('/dev/udfs-directory/udfs-01.udfs') SAV DEV('/QSYS.LIB/TAP02.DEVD') OBJ(('/dev/udfs-directory/udfs-02.udfs')