Weijia Song

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—Data center applications present significant opportunities for multiplexing server resources. Virtualization technology makes it easy to move running application across physical machines. In this paper, we present an approach that uses virtualization technology to allocate data center resources dynamically based on application demands and support green(More)
Infrastructure as a Service (IaaS) clouds couple applications tightly with the underlying infrastructures and services. This vendor lock-in problem forces users to apply ad-hoc deployment strategies in order to tolerate cloud failures, and limits the ability of doing virtual machine (VM) migration and resource scaling across different clouds. This paper(More)
—Cloud computing allows business customers to scale up and down their resource usage based on needs. Many of the touted gains in the cloud model come from resource multiplexing through virtualization technology. In this paper, we present a system that uses virtualization technology to allocate data center resources dynamically based on application demands(More)
In this paper, we explore the use of live VM migration to take advantage of spot markets such as provided by Amazon and Google. These markets provide an exciting low cost alternative to regular VM instances, but the threats of price spikes and premature termination severely limit their usability. Migration can address these threats: spot market instances(More)
Global cloud services have to respond to workloads that shift geographically as a function of time-of-day or in response to special events. While many such services have support for adding nodes in one region and removing nodes in another, we demonstrate that such mechanisms can lead to significant performance degradation. Yet other services do not support(More)
Deterministic replay, which provides the ability to travel backward in time and reconstruct the past execution flow of a multiprocessor system, has many prominent applications. Prior research in this area can be classified into two categories: hardware-only schemes and software-only schemes. While hardware-only schemes deliver high performance, they require(More)
A Supercloud is a "CrossCloud": It is an Infrastructure-as-a-Service (IaaS) that goes beyond federated or hybrid clouds and gives its users direct control over cloud deployments--even across different underlying cloud providers (Jia et al. 2015). It supports privileged cloud operations such as migration across autonomous cloud providers even if they use(More)
Many applications perform real-time analysis on data streams. We argue that existing solutions are poorly matched to the need, and introduce our new Freeze-Frame File System. Freeze-Frame FS is able to accept streams of updates while satisfying "temporal reads" on demand. The system is fast and accurate: we keep all update history in a memory-mapped log,(More)
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