Defining Virtual Disks in Storage

A virtual disk in storage is another type of temporary minidisk that you can attach to your virtual machine for the duration of a terminal session. However, because a virtual disk in storage is allocated from system storage instead of on a real DASD, and so avoids the I/O overhead of writing to the DASD, it may be faster to use than a regular temporary minidisk.

Use the CP DEFINE command to create a virtual disk in storage. A virtual disk in storage is always defined as an FBA minidisk, which is allocated in 512-byte blocks. You do not need to have a real FBA DASD on your system. For example, the following command allocates a 160-block virtual disk in storage and assigns it a virtual device number of 333:

define vfb-512 as 333 blk 160

For more information, see z/VM: CP Commands and Utilities Reference.