Technical and Business Considerations
Virtualization may not be ideal for complex systems that have high workloads with little use for resource sharing and replication. A poorly formulated virtualization plan can result in excessive performance overhead. A common strategy used to rectify the overhead issue is a technique called para-virtualization, which presents a software interface to the virtual machines that is not identical to that of the underlying hardware. The software interface has instead been modidied to reduce the guest operating system's processing overhead, which is more difficult to manage. A major drawback of this approach is the need to adapt the guest operating system to the para-virtualization API, which can impair the use of standard guest operating systems while decreasing solution portability.
Special Hardware Compatibility
Many hardware vendors that distribute specialized hardware may not have device driver versions that are compatible with virtualization software. Conversely, the software itself may be incompatible with recently released hardware versions. These types of incompatibility issues can be resolved using established commodity hardware platforms and mature virtualization software products.
The programmatic and management interfaces that establish administration environments for a virtualization program to operate with various virtualization solutions can introduce portability gaps due to incompatibilities. Initiatives such as the Open Virtualization Format (OVF) for the standardization of virtual disk image formats are dedicated to alleviating this concern.