Green cluster of low-power embedded hardware server accelerators .

摘要

Power consumption is the largest operating expense in any server farm. In this thesis, we provide a cluster of low cost and low-power embedded hardware accelerators that can perform simple application level serving tasks (e.g. dynamic and static web hosting). The cluster can either replace powerful servers or can be used as extra torque for peak traffic moments. The cluster can boot in less than 10 seconds allowing rapid deployment into the network. The cluster will just provide enough acceleration to pass the service level agreement (SLA) on peak traffic moments in contrast to bringing a powerful server to the network , which may be overkill solution for the surge of traffic.;We also implement our system using micro-controller boards as accelerator and Linux as the operating system. We intensively tested out proposed system in order to compare it with the state of the art powerful servers. Real traffic is generated for the testing of the cluster. The result is that a tiny accelerator by itself is slower than a powerful server (7-11 times slower). However it only consumes about 1-2% of the energy used by powerful Internet servers.;If the objective is not minimizing the time of serving a request but rather increasing the throughput and maintaining the required SLA, a cluster of embedded controllers could be used in order to handle the same amount of traffic as a powerful state of the art Internet server. The proposed accelerator cluster is using 8 times lower energy in comparison to a powerful server while handling the same amount of traffic and producing response times that are only 7 toll times slower. Adaptive admission-based controls are also implemented to provide SLA grantee on quality of service (QoS) of the cluster.;We also propose a new technique for admission control in order to enforce the SLA by dropping selective requests instead of overloading the entire system and slowing down every body. Simulation using Matlab shows that our proposed scheme outperforms previously known admission control policies in the case of M/G/1 system assumption (e.g. a general memoryless stochastic system).