I have a few customers running some Chinese stuff called "crystalminescache". I am not sure what this is, but it uses a lot of bandwidth and a lot of hard drive I/O. I have limited the bandwidth but am having problems with the I/O overloading my disks. Iostat reports my raid is constantly at 100% utilization due to these customers. What can I do to lower their I/O priority or limit their disk speed?