IBM Redbook: The System Administrator's Companion
From Support
This IBM Redbook covers several backup and restore topics including creating, backing up and restoring a user defined file system (UDFS) on the iSeries.
The second attachment talks about creating a UDFS in an alternate disk ASP.
A UDFS file system can be mounted and unmounted. This allows a user to:
1.) Backup and restore individual IFS files with the SAV command. This requires the UDFS to be mounted over a regular IFS folder.
**Note: This individual file method of backup can be slower if you have several thousand or million documents in a directory.
2.) Backup and restore the entire stream/block file with the SAV command. This requires the UDFS to be unmounted so the entire IFS block file can be saved or restored. A limitation with this approach is that you are saving and restoring the entire UDFS image during each backup.
**Note: This single file method of backup can be faster because the entire disk space is backed up as a single file, thus improving tape drive throughput.
Read section 15.3 for detailed information on setting up a User Defined File System or backing up and restoring the UDFS.
