i read this in the 8.0 hardware sizing guide
Virtualization
AirWave can run in a virtualized environment. To ensure scalability, dedicate the processing and memory. You must
also ensure that the disk subsystem can maintain the IOPs throughput as detailed below.
Most virtualized environments use a shared disk subsystem assuming that each application will have bursts of I/O
without a sustained high I/O throughput. AirWave requires a continuous sustained high data I/O rate.
Aruba recommends a 20% increase buffer for virtual environments. Ensure you allocate enough extra disk space for the
OS and swap when partitioning the virtual disk.
which i read as in general take 20% extra for a virtualized environment and make sure it is dedicated for this.