I/O Request Workflow Using Hyper Parallel Access Volumes - HPE XP7 User Manual

parallel I/Os is the number of aliases assigned to the base plus 1 for static or dynamic configurations.
When HPAV is used, the maximum number of parallel I/Os to a base address is the number of aliases
configured in the CU plus 1. If multiple base devices are using aliases, the maximum number for any
individual base device is reduced accordingly.
In the following figure, three alias devices are each 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. Since alias devices A, B, and C were assigned to
base device 1 in advance of the operation, I/O requests are automatically issued to these alias devices.
Similarly, if a host computer accesses base devices 2 and 3, the I/O requests are automatically issued to
the alias devices assigned to those two base devices. Base device 4 is not able to process multiple I/O
requests since an alias device is not assigned to the device.

I/O request workflow 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 HPAV, alias devices are pooled together in each CU. All base devices in the CU share
the alias devices as a pool. The aliases are assigned to a specific base address for the duration of the I/O
and then returned to the alias pool for the CU.
In the following figure, three alias devices each are assigned to base devices 1, 2, and 3.
10 I/O request workflow using Hyper Parallel Access Volumes