A traditional save to a single device produces one tape file on the tape media.
You can perform a save operation while using more than one media devices
simultaneously. Integrated File System data saved by a single SAV command
using multiple devices will be in a parallel save format. The data
is spread across the media devices. If you use Backup, Recovery and Media
Services (BRMS), the save format is also parallel.
Note: Using a media definition
to save your Integrated File System data to a single device specified in a
*MEDDFN is the same as specifying that device on the SAV command. It is
not beneficial to use a *MEDDFN when saving to a single device. The data
is saved in serial format.
| Save scenario | Using SAV command | Using BRMS |
|---|---|---|
| Save integrated file systems to multiple devices | Parallel | Parallel |
This table shows the correlation between the Integrated File
System being saved and the name of the media files being produced.
| Data saved | Number of devices | Format | Tape media files produced |
|---|---|---|---|
| Integrated File System data | 1 | Serial | SAVdatetime |
| Integrated File System data | 2 | Parallel | Device 1: SAVdatetime Device 2: SAVdatetime |
Once you create a media definition, a convenient way to save the entire Integrated File System to multiple devices is to specify SAV DEV (’/QSYS.LIB/Y.LIB/X.meddfn’) OBJ ((’/*’) (’/QSYS.LIB’ *OMIT) (’/QDLS’ *OMIT).
Backup Recovery Media Services/400 (BRMS) provides an easy to use interface that allows you to perform parallel save operations without creating a media definition. You specify which tape devices to use in parallel, and BRMS builds and manages the media definition for you.
- Note: Performing a parallel save with large objects may improve performance. However, if saving small objects, the performance may decrease.
- Note: Restoring individual objects from a parallel save may take a substantial amount of time.