Set up virtual tape storage

This topic provides a high-level overview of the steps used to set up virtual tape storage. This topic also provides links to information that provide specific instructions for setting up virtual tape storage based on what task you want to accomplish.

Here is a high-level overview of how to set up virtual tape storage for the most common tasks. The exact steps you use to set up virtual tape storage depend on what task you want to accomplish, such as performing a save operation or distributing software.

The specific tasks provide links to instructions for the different tasks that you can perform with virtual tape storage.

The tasks are as follows:

Create virtual devices
Create virtual images in an image catalog
Use virtual images in an image catalog
Specific tasks

Create virtual devices

If you do not already have a virtual tape device type 63B0, create one and vary it on:

CRTDEVTAP DEVD(TAPVRT01) RSRCNAME(*VRT)
VRYCFG CFGOBJ(TAPVRT01) CFGTYPE(*DEV) STATUS(*ON)

Note: You can create up to 35 virtual tape devices.

Create virtual images in an image catalog

Create the image catalog:

CRTIMGCLG IMGCLG(MYCATALOG) DIR('/MYCATALOGDIRECTORY') TYPE(*TAP)

Add the virtual tape volume from an existing virtual tape file or create a new virtual tape volume.
- To add images from an image file:
```
ADDIMGCLGE IMGCLG(MYCATALOG) FROMFILE(SLIC_N) TOFILE(*fromfile)
```
  Repeat this step for each file in your catalog directory. This step assumes your image is already in the image catalog directory.
- To create new virtual tape volumes:
```
ADDIMGCLG IMGCLG(MYCATAGLOG) FROMFILE(*NEW) 
TOFILE(vo1001) VOLNAME(VOL1001)
```

Use virtual images in an image catalog

Load the image catalog in the virtual device

LODIMGCLG IMGCLG(MYCATALOG) DEV(TAPVRT01)

Specific tasks

You can perform save and restore operations with virtual tape storage.

Perform a save operation

To save to virtual tape storage, see Consider using virtual tape storage in the Backup up your server topic.

Perform a restore operation

To restore from virtual tape storage, see Backup and Recovery Link to PDF

Duplicating virtual tape to physical media

When you plan to duplicate the virtual tape volumes to physical tape devices you will need to make sure that the virtual tape volumes are created using a block size that is compatible with your physical tape device. The density (format) of the virtual tape volumes is used to control the maximum size that is used for the blocks of data on the virtual tape volume. . If you are unsure what block size your tape device supports, you can view the supported block size information by using iSeries™ Navigator to display the properties of your physical tape device.

Using volumes in dependent image catalogs

A dependent catalog provides a read-only view of the virtual tape volumes that are within a reference image catalog. To create dependent image catalogs use the following command:

CRTIMGCLG IMGCLG(JOEDEP) DIR(*REFIMGCLG) TYPE(*TAP) REFIMGCLG(JOE)

All of the volumes in the reference image catalog (JOE) are accessible when the dependent image catalog (JOEDEP) is mounted in a separate virtual tape device. The dependent image catalogs are not synchronized with additional changes that are made to the reference image catalog.

Multiple dependent image catalogs can be created all pointing to the same reference catalog. The same virtual tape volume can be mounted in several virtual devices at the same time through the use of dependent image catalogs. This mounting procedure enables the same virtual tape volume to be used for input operations by multiple users at the same time.

Using virtual tape from other partitions

Make sure that the virtual tape device description has unload at vary off with parameters specifying *NO.
Mount the virtual volume you want to use from the other partition using the image catalog commands.
Vary off the virtual tape device.
Note: The virtual volume is still mounted.

The other partition can now use the previously mounted virtual tape volume through virtual I/O to the virtual tape device.

Using virtual tape volumes in user ASP's

CRTUDFS '/dev/qaspXX/aspXX.udfs', where XX is the ASP number
MKDIR ‘/your-path’ to make a mount point directory
MOUNT *UDFS ‘/dev/qaspXX/aspXX.udfs’ ‘/mount-point-directory’
Now anything you create in ‘/mountpoint’ is created in the UDFS
Use the CRTIMGCLG command to create an image catalog with the mount point in the path name

Note: You cannot specify the mount-point directory when specifying a path-name with the CRTIMGCLG command. Only the directory below the mount-point can be specified.

Using virtual tape volumes in independent ASP's

To use a virtual tape volume in an independent ASP specify the ASP device name as the first part of the IFS path name. The independent ASP must be varied on before the virtual tape volumes are usable, so certain restore commands, such as RSTLICPGM can not be used for virtual tape volumes in independent ASPs.

Image files *ALWSAV attributes

When the image catalog is in ready status all of the image catalog's images have a *ALWSAV attribute value of *NO. This does not allow the images to be saved by the Save Object (SAV) command or the QsrSave API. When the image catalog is not in ready status all of the image catalog's images have a *ALWSAV attribute value of *YES. This allows the images to be saved.