Thursday, June 24, 2010

Stout: An Adaptive Interface to Scalable Cloud Storage

I just noticed that SleepServer is not the only UC San Diego computer science paper being presented this week at the 2010 USENIX Annual Technical Conference in Boston.

"Stout: An Adaptive Interface to Scalable Cloud Storage," John C. McCullough, University of California, San Diego; John Dunagan and Alec Wolman, Microsoft Research, Redmond; Alex C. Snoeren, University of California, San Diego.

The abstract is below:

Many of today's applications are delivered as scalable, multi-tier services deployed in large data centers. These services frequently leverage shared, scale-out, key-value storage layers that can deliver low latency under light workloads, but may exhibit significant queuing delay and even dropped requests under high load. Stout is a system that helps these applications adapt to variation in storage-layer performance by treating scalable key-value storage as a shared resource requiring congestion control. Under light workloads, applications using Stout send requests to the store immediately, minimizing delay. Under heavy workloads, Stout automatically batches the application's requests together before sending them to the store, resulting in higher throughput and preventing queuing delay. We show experimentally that Stout's adaptation algorithm converges to an appropriate batch size for workloads that require the batch size to vary by over two orders of magnitude. Compared to a non-adaptive strategy optimized for throughput, Stout delivers over 34x lower latency under light workloads; compared to a non-adaptive strategy optimized for latency, Stout can scale to over 3x as many requests.

PCs Sleep (and Work) Through the Night with SleepServer

Leaving your computer on all night/weekend/break just in case you need to connect remotely…that’s SO last decade. UC San Diego computer scientists created software that lets you put your computer to sleep without worrying that you’ll have to schlep your way to campus on Saturday night just because you suddenly need to access your computer connected to an enterprise network. SleepServer wakes up your sleeping PC remotely when you need it…but it won’t wake up the PC if the PC’s alter ego – a lightweight virtual image – can handle the job.

That’s the simplest example of how SleepServer helps UC San Diego cut its carbon footprint. But SleepServer does much more. That sleeping computer of yours also remains active on voice over IP/IM/peer-to-peer networks as well thanks to SleepServer.

How is this possible? When you put your computer to sleep, the software activates a lightweight virtual image of your PC which runs on a commodity server, along with hundreds of images of other PCs on your network. That virtual image can do a number of basic things that would otherwise require the actual PC to be awake.

SleepServer reduces energy consumption on enterprise PCs previously running 24/7 by an average of 60 percent, according to a new study presented today at the 2010 USENIX Annual Technical Conference.

Yuvraj Agarwal from UC San Diego is presenting this work TOMORROW June 25 in Boston at the 2010 USENIX Annual Technical Conference.

Read the story here.