John M. Acken ¹ and Naresh K. Sehgal ², ¹ Portland State University, Oregon, ² Securing the Cloud, California

One of the biggest challenges for an IT administrator in a private or public data centre is to ensure a fair usage of resources between different Virtual Machines (VMs). If a particular VM does excessive network traffic, I/O or memory access, then other VMs running on that same server will experience a slowdown in their access of the same resource. This phenomenon is called noisy neighbours and results in a performance variation experienced by users over time, due to over consumption of shared resources by other VMs. This interference will occur even if each VM has adequate resources for its assigned workload due to conflict in the shared server resources. In this paper, we look at real-life data from Cloud based VMs showing the performance variability and present methods to detect it. A variation of this phenomenon is when a noisy neighbours can decipher confidential contents of a victim VM. We term it as a nosy neighbour, which can pose security risks. We present specific methods to prevent both noisy and nosy neighbours.

Cloud, Performance, Multi-tenants, Virtual Machines, Security, Noisy Neighbour, Nosy Neighbour