On fault tolerance in data center network virtualization architectures

A Virtual Data Center (VDC) is a combination of interconnected virtual servers hosted on a physical data center that hosts multiple such VDCs. This enables efficient sharing of the data center´s resources while handling dynamically changing resource requirements of the clients. The SecondNet architecture (Guo et. al, 2010) realizes this VDC concept and includes a centralized VDC resource-mapping (virtual to physical) algorithm. Fault tolerance is an important requirement in data center based services, in order to increase reliability and availability. In this paper, we propose a fault tolerance mechanism to handle server failures by efficiently migrating the Virtual Machines (VMs) hosted on the failed server to a new location. We observed that we were able to recover all the faults, even for a server utilization of 90%. In order to reduce the impact of server failures on the VDCs hosted in the data center, we present a new load balancing scheme based on clustering that efficiently allocates the VDCs on the data center. Using this scheme, we were able to reduce the affected number of VMs per server failure by 63%, in case of a BCube network of size 625 nodes, and by 86%, in case of a BCube network of size 1296 nodes.