Hallo Bodo,
vielleicht hilft Dir dies weiter:
When any image catalog is in a READY Status and the WRKIMGCLG command and a *LINK, SAVBRM , or SAV is run for that directory, the stream files are not saved. If the image catalog is in a Not Ready status, the image catalog entries will be saved and this could result in significant increase in the amount of data being saved. After creating virtual tape images, they are automatically included when performing a full system save using GO SAVE , Option 21. The virtual tape images could significantly increase the time it takes to complete the Option 21 save operation, even if the image catalog entries do not contain data. To exclude the virtual images from a full system save, use one of the following strategies:

-- Use the Change Attribute ( CHGATR ) command to mark the image catalog directory as non-saveable. For example:

CHGATR OBJ('/Catalog-Path') ATR(*ALWSAV) VALUE(*NO)

-- Use the Load Image Catalog ( LODIMGCLG ) command to make the image catalog ready. Image catalogs with a ready status are omitted from the save. In an attended save, omitting the image catalog directories can be specified on the Save Object ( SAV ) command.
o It is recommended that PTF MF41110 be loaded and applied before using virtual tape. More information can be found in APAR MA34516. The initialize Tape (INZTAP) command makes any pre-existing data on the virtual tape volume inaccessible by the virtual tape device. Running the INZTAP command and specifying CLEAR(*YES) can be used to delete any existing data in a virtual tape volume; however, this should be used only if there are security concerns with the existing data because this operation can take a long time and uses significant system resources.

It is recommended that PTF MF41110 be loaded and applied before using Virtual tape. More information can be found in APAR MA34516 Rochester APAR Database.