C.3. Application Restrictions

There are aspects of virtualization that make it unsuitable for certain types of applications.

Applications with high I/O throughput requirements should use KVM's paravirtualized drivers (virtio drivers) for fully-virtualized guests. Without the virtio drivers, certain applications may be unpredictable under heavy I/O loads.

The following applications should be avoided due to high I/O requirements:

You should carefully evaluate applications and tools that heavily utilize I/O or those that require real-time performance. Consider the virtio drivers or PCI device assignment for increased I/O performance. For more information on the virtio drivers for fully virtualized guests, see Chapter 5, KVM Paravirtualized (virtio) Drivers. For more information on PCI device assignment, see Chapter 16, Guest Virtual Machine Device Configuration.

Applications suffer a small performance loss from running in virtualized environments. The performance benefits of virtualization through consolidating to newer and faster hardware should be evaluated against the potential application performance issues associated with using virtualization.