When a save operation spans a volume, it pauses the save process when the current piece of media you are using runs out of space and it continues the save operation on the next piece of media. In the context of backup and recovery, a volume is the media that you are using to save your data. Spanning occurs when the volumes have files that continue from one volume to the next.
When you perform a save operation and span virtual images, the multivolume set of virtual images behaves just like a multivolume set of any form of actual media.
One advantage of using virtual storage for a backup operation is that if you have enough disk space, you can perform unattended backups without the use of a media autoloader or a media library.
Similar to actual devices, when you span volumes of virtual images, you can specify a volume list or specify *MOUNTED for the VOL parameter on all of the save commands. If you specify a volume list, the server mounts the volumes of virtual images when they are needed. If you specify *MOUNTED, you must have the virtual images mounted when you start the command. In either case, you must provide enough volumes to complete the save operation.
Whether you specify *MOUNTED or a volume list, if you do not provide enough volumes to complete save operation, the server sends you inquiry message OPT149F - Load next volume on optical device &1. Inquiry message OPT149F provides you with three options:
If you allow the server to create a new volume for you, the server does the following:
When the server creates a new volume, the server gives the new virtual image a name. The server uses a time stamp for the volume ID. The image name is a combination of volume ID and the volume sequence number. The server inserts the new virtual image in position 256 of the image catalog. The size of the new virtual image is the same as the previous virtual image.
The following table shows an example of what happens when the server adds two new volumes during save to an image catalog where Volume 2 existed before starting the save.
| Index | Volume ID | Virtual image name | Volume sequence number | Size | Description |
|---|---|---|---|---|---|
| 1 | Volume1 | File1 | 1 | 1300 MB | My Save 1 |
| 2 | Volume2 | File2 | 2 | 650 MB | My Save 1 |
| 253 | 030311124115 | 0303111241150003 | 3 | 650 MB | SET ID VOLUME1 SEQ |
| 254 | 030311124330 | 0303111255320004 | 4 | 650 MB | SET ID VOLUME1 SEQ |
| 255 | 030311124545 | 0303111256450005 | 5 | 650 MB | SET ID VOLUME1 SEQ |
| 256 | 030311124801 | 0303111248010006 | 6 | 650 MB | SET ID VOLUME1 SEQ |
If you are doing a full backup, with the Save System (SAVSYS) command for example, the first volume must be least 1489 MB. The first volume must be at least 1489 MB because the first volume must be large enough to save the Licensed Internal Code. The remaining volumes can be smaller than 1489 MB.
