Physical Data Center Research Articles

Modeling and Evaluation of Energy Policies in Green Clouds

Following the as-a-service philosophy, a cloud service provider offers computing utilities in the form of virtual resources instantiated on top of a physical infrastructure. In order to meet business requirements still providing high-quality services, performance evaluation needs to be carefully carried out with the aim of optimizing data center utilization and increasing user satisfaction. In this context, power efficiency plays a critical role pushing service providers towards the application of innovative green strategies. In this paper, we present an analytical framework, based on stochastic reward nets, that allows to evaluate different resource allocation policies in a green cloud. A use case is shown in order to illustrate the approach, modeling scattering and saturation allocation policies and comparing them to a purely physical data center scenario. A validation of the proposed model against the CloudSim framework is presented and several numerical results are provided, demonstrating the effectiveness of the approach as a powerful tool for a cloud service provider to perform well-informed decisions about the resource allocation policies to be enforced.

Virtual network function embedding in real cloud environments

Future network architectures will be completely reshaped by the emerging Network Function Virtualization (NFV) paradigm, and telco operators will likely deploy flexible infrastructures based on the cloud, offering programmable connectivity services and computing/storage facilities in the form of Virtual Data Centers (VDCs). This paper introduces and discusses some challenging technical issues associated with this promising approach, with a special focus on the exploitation of industry-relevant cloud platforms, such as OpenStack, and on network-aware optimal placement problem of entire VDCs, taking into account multiple virtual (Virtual Machines – VMs, virtual networks, …) and physical (host capacities, network topology and capacity, …) resources and constraints. The proposed placement, computed for real production OpenStack deployments, not only satisfies the predicted communication for all VDCs deployed atop the same physical data center, but also accounts for the (real) computing overhead due to intense communication load of VMs co-located on the same physical host, such as in the case of Virtual Network Functions (VNF) embedding, typically neglected by similar existing works.

Traffic-aware VDC embedding in data center: A case study of fattree

Virtualization is a common technology for resource sharing in data center. To make efficient use of data center resources, the key challenge is to map customer demands (modeled as virtual data center, VDC) to the physical data center effectively. In this paper, we focus on this problem. Distinct with previous works, our study of VDC embedding problem is under the assumption that switch resource is the bottleneck of data center networks (DCNs). To this end, we not only propose relative cost to evaluate embedding strategy, decouple embedding problem into VM placement with marginal resource assignment and virtual link mapping with decided source-destination based on the property of fat-tree, but also design the traffic aware embedding algorithm (TAE) and first fit virtual link mapping (FFLM) to map virtual data center requests to a physical data center. Simulation results show that TAE+FFLM could increase acceptance rate and reduce network cost (about 49% in the case) at the same time. The traffic aware embedding algorithm reduces the load of core-link traffic and brings the optimization opportunity for data center network energy conservation.

Virtualizing networking and security in the cloud

Virtualization of computer workloads onto powerful x86 multicore platforms is leading to a massive transformation in the way services are produced by next generation data centers. Simultaneously, cloud computing principles are compelling a rethink in the way enterprises are beginning to consume such services. In this paper, we present the need for network and security (netsec) functions, which are currently realized in hardware appliances, to significantly evolve to keep pace with these new trends, and to provide "disruptively simplified" security that was not earlier possible With server consolidation and desktop virtualization, significantly more traffic remains within the data center racks, leading to blind spots for "in network" security appliances. Current netsec devices which are architected based on "scale up" principles cannot keep pace with increased bandwidth driven to the servers, and the ever increasing volume of threats at all layers of the network stack. Also, highly mobile workloads and increasing intelligence in the virtual/hypervisor layer, makes it increasingly hard for static network devices to interlock with dynamic policy changes and onthe- fly re-purposing of resources to serve different workloads, applications, or users This paper highlights a new trend in the industry to virtualize netsec functions inside security virtual appliances (SVAs), which can then be placed on hosts, and offer distributed security functions for network flows across the cluster. We analyze this trend in detail using the VMware vShield product line as an example. The approach replaces single choke-point based physical security devices like firewalls, IP address Management (IPAM), flow monitoring, and data leakage prevention (DLP) with distributed virtual counterparts running on slices of x86 co-located with compute workloads with ability to tap into traffic going in and out of virtual machines (VMs) vShield's distributed scale-out architecture means performance can scale up or down linearly as new SVAs are added, while simplifying the lifecycle management of these SVAs including installs, upgrades, ability to debug, and reliability by leveraging underlying virtualization primitives of VM cloning, deploy from template, and VM high availability and fault tolerance. Interactions with features like live migration (vmotion) of guest VMs and distributed power management of host servers introduce new aspects of appliance management that was not possible in the physical world. The paper analyzes these aspects of SVA management in depth. Our measurements of the security inspection throughput for given vCPUs and memory indicate it is comparable to those of physical counterparts with the additional flexibility of a scale-out deployment. Further, we demonstrate that with this approach a virtual datacenter (VDC) in the cloud can be deployed in minutes compared to days/weeks with physical datacenters. Finally, we present the additional security inspections that can be performed in the virtual world that were not possible in the physical world. The ability of SVAs to introspect traffic into and out of VMs implies they can perform checks for MAC spoofing, IP spoofing [6], ARP filtering at the source. Furthermore, based on security analysis if a VM is deemed suspect it can be quickly quarantined Concepts such as flow introspection, automated insertion of SVAs into flows at VM ingress/egress, distributed scale out architecture across a cluster of hosts, encapsulation of secure VDCs, and programmability of security policies via RESTful interfaces, represent a significant architectural change, with wide applicability in enterprise data centers, and private/public cloud environments.

Improving data-center efficiency for a Smarter Planet

In 2009, IBM launched its Smarter Planet™ initiative, which is based on the paradigm that virtually any physical object, process, or system can be instrumented, interconnected, and infused with intelligence. Because of the increased demand for information technology (IT) to facilitate Smarter Planet solutions, physical data centers have become interconnected, instrumented, and intelligent (i.e., adaptable, scalable, energy efficient, and cost effective). “Green data centers,” which are discussed in this paper, are those that make use of facilities and IT integration, resulting in lower energy costs, reduced carbon footprint, and reduced demand for power, space, and cooling resources. This paper reviews energy-efficiency strategies that are being incorporated in eight million square feet of data-center space that IBM operates in support of its customers. These strategies include both a dynamic infrastructure IT initiative and an energy-efficiencies pillar of the IBM New Enterprise Data Center initiative. For example, compared to nonmodular designs, implementation of a modular design to optimize expandable data centers will better match the IT demand with the data-center energy supply. This high-level overview describes the integration of these strategies to create a class of leading-edge IBM data centers and a plan for the optimization of existing data centers.

Space Weather applications with CDPP/AMDA

AMDA (Automated Multi-Dataset Analysis), a new data analysis service, recently opened at the French Plasma Physics Data Center (CDPP). AMDA is developed according to the Virtual Observatory paradigm: it is a web-based facility for on-line analyses of space physics. Data may come from its own local database as well as remote ones. This tool allows the user to perform classical manipulations such as data visualization, parameter computation and data extraction. AMDA also offers innovative functionalities such as event searches on the content of the data in either visual or automated ways, generation, use and management of time tables (event lists). The general functionalities of AMDA are presented in the context of Space Weather with example scientific use cases.

Data Processing in Cosmic Rays at the Institute of Physical and Chemical Research-World Data Centers

Data Processing in Cosmic Rays at the Institute of Physical and Chemical Research-World Data Centers