Virtual tape media
You can use virtual tape devices to save data directly to system disk units for convenience, flexibility, and in some cases improved performance. These scenarios will give you some examples of ways that you can utilize virtual tape in your save environment.
Virtual tape is beneficial for unattended saves because it eliminates media errors that could stop an unattended save operation. If you do not allocate enough space in the virtual volumes within the image catalog to save the intended information, virtual tape will use the auto-generate feature to create additional virtual tape volumes.
Ability to duplicate to physical media
Saving data to virtual tape media
Perform the following steps to save data to virtual tape media. The device and catalog names used here are examples. Perform steps 2 through 5 only if you have not previously created a virtual tape device, image catalog, and images to use for the save operation.
- Ensure that the system has enough disk space to hold all the virtual images you are going to create for your save operation.
- Create a virtual tape device. (You can create
up to 35 virtual tape devices.)
CRTDEVTAP DEVD(TAPVRT01) RSRCNAME(*VRT) ONLINE(*YES) TEXT(text-description)
- Vary on the virtual tape device.
VRYCFG CFGOBJ(TAPVRT01) CFGTYPE(*DEV) STATUS(*ON)
- Create an image catalog and virtual volumes for your save
operation.
CRTIMGCLG IMGCLG(MYCATALOG) DIR('/MYCATALOGDIRECTORY') CRTDIR(*YES) ADDVRTVOL(3) PREFIX(ABC) IMGSIZ(10000) TEXT(catalog-description) TYPE(*TAP)
- Load the image catalog. This step associates the virtual tape
device to the image catalog. Only one image catalog at a time can be associated
with a specific virtual tape device.
LODIMGCLG IMGCLG(MYCATALOG) DEV(TAPVRT01) OPTION(*LOAD)
- Run a save command listing the virtual tape device in the DEV parameter. Virtual tape devices operate similar to tape media library devices so entering the volume names in the volume parameter automatically mounts the volumes.
Exclude virtual images from a full save
After you create virtual tape images, they will automatically be included when you perform 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. If you want 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 will be omitted from the save operation.
- In an attended save, you can specify to omit the image catalog directories on the Save Object (SAV) command.