Using HyperPAV Minidisks

In the context of HyperPAV, the real I/O scheduling algorithms for full-pack and non-full-pack minidisks behave in the same manner.

A guest virtual machine can define one or more minidisk volumes that exist on a real HyperPAV volume. The real HyperPAV volume has a real base and is associated with a pool that also contains zero or more HyperPAV aliases.

All HyperPAV I/O operations that are directed to a minidisk volume are optimized by the z/VM® automatic selection of an appropriate real HyperPAV base or alias subchannel for the underlying real volume. In other words, the scheduling of I/O to a virtual device will be dynamically scheduled and multiplexed on any real HyperPAV base or alias subchannel that is defined in the hardware. This gives z/VM the flexibility to choose a real HyperPAV base or alias subchannel that is not in use at the time. For example, if users GUEST1 and GUEST2 simultaneously issue an I/O request to two different minidisk volumes that are defined on the same real underlying volume, via their respective virtual subchannels, the result would be that one I/O would be executed on the real base subchannel and the other, simultaneously, would be executed on a real alias subchannel.