Oct 3 - On Fragmentation in Virtualized Data Centers


Join the CS department for a talk at 12n in Room 120 as we welcome Prof. Umesh Bellur from IIT Bombay. All are welcome to attend and CSE 600 students receive credit.


Existing virtual machine (VM) placement schemes have measured their effectiveness by measuring how well they conserve either Physical Machine’s resources(CPU, memory) or the network resource but not both. However, real applications use all resource types to varying degrees. The result of applying existing placement schemes to VMs running real applications is a fragmented data center where resources along  one dimension become unusable even though they are available because of the unavailability of resources along other dimensions. An example of this fragmentation is unusable CPU because of a bottlenecked network link from the physical machine which has available CPU. To date, evaluations of the efficacy of VM placement schemes has not recognized this fragmentation and it’s  ill effects, let alone try to measure it and avoid it. In this talk, I will first define the term "relative resource fragmentation" and illustrate how it can be measured in a data center. The metric we put forth for capturing the degree of fragmentation is comprehensive and includes all key data center resource types. We then propose a scheme of minimizing this fragmentation so as to maximize the availability of existing set of data center resources. Results of empirical evaluations of our placement scheme compared to existing network based placement schemes show a reduction of fragmentation by as much as 15% and increase in number of successfully placed applications by up to 20%. 

Umesh works on virtualization and cloud computing, and has recently published in leading cloud venues including SOCC and IEEE Cloud.