cvaffinity can be used to assign an affinity to a storage pool in Xsan. An affinity maps a specified directory to a storage pool. Therefore, if you have a dedicated capture station and you want to make sure it always has 4gbps of throughput then you can create a storage pool called capture, mark it for use with affinity only, create a folder called capture and assign the affinity for the capture storage pool to the capture folder on the volume. Now all data written to that folder will be written through the affinity and therefore provide a certain level of Quality of Service to that affinity.