HP XP P9500 Storage - Manual (Page 8)

Flow of I/O requests using Hyper Parallel Access Volumes
Multiple alias devices are assigned to a base device in a CU to enable the base device to handle
multiple I/O requests. In Hyper Parallel Access Volumes, alias devices are pooled together in a
single CU, meaning that all base devices in the CU share alias devices.
In the following figure, three alias devices each are assigned to base devices 1, 2, and 3. As
illustrated with the arrows in the figure, I/O requests converge on base device 1 when a host
computer accesses the device using Parallel Access Volumes. I/O requests are automatically issued
to unused alias devices among the nine alias devices in the CU. Similarly, if a host computer
accesses base devices 2, 3, and 4, the I/O requests are automatically issued to unused alias
devices among the nine alias devices. Base device 4 is able to process multiple I/O requests even
though no alias devices are specifically assigned to the device.
8 Overview