Modeling of I/O Performance Interference in Virtualized Environments with Queueing Petri Nets

Virtualization technology allows to share the physical resources used in IT infrastructures for efficient and flexible system operation. Sharing of physical resources, however, comes usually at the cost of performance and poses significant challenges to respect the Quality-of-Service of consolidated data-intensive applications due to the mutual performance interference among the applications. The non-trivial impact of workload consolidation on the I/O performance can be anticipated using explicit performance analysis techniques. In current practice, however, explicit modeling of I/O performance interference effects in virtualized environments is usually avoided due to their complexity. In this paper, we present an explicit performance modeling approach of I/O performance interference in virtualized environments with queueing Petri nets (QPNs). More specifically, we first highlight major challenges when modeling I/O performance in virtualized environments. Then, we create a single-VM I/O performance model calibrated with response time measurements to capture the complex behavior of a representative, real-world environment based on IBM System z and IBM DS8700 server hardware. Finally, we use the I/O performance model to evaluate the I/O performance when the workload is distributed heterogeneously on colocated virtual machines. Overall, we effectively create an I/O performance interference model capturing the I/O performance effects in a multi-VM environment with less than 10% prediction error on average.