Avoiding shared disks

With SU /390 avoid 'shared' disks as much as possible.

Refer to the information on exclusive and "shared" assignment in section "Peripherals".

Measurements have shown that with more than one guest system the VM2000 overhead increases by 0.4% for every 100 I/O operations per second on disks which are assigned as “shared”.

• Limit the use of disks assigned as “shared” under VM2000 to the necessary degree.