Emerging large-scale scientific applications involve massive, distributed, shared data collections (petabytes), and require robust, high performance for read-dominated workloads. Achieving robust performance (low variability) in storage systems is difficult. We propose RobuSTore, a novel storage technique, which combines erasure codes and speculative access to reduce performance variability and...

We consider the problem of migrating user data between data centers. We introduce distributed storage overlays, a simple abstraction that represents data as stacked layers in different places. Overlays can be readily used to cache data objects, migrate these caches, and migrate the home of data objects. We implement overlays as part of a key-value object store called Nomad, designed to span man...

Fully distributed storage systems have gained popularity in the past few years because of their ability to use cheap commodity hardware and their high scalability. While there are a number of algorithms for providing differentiated quality of service to clients of a centralized storage system, the problem has not been solved for distributed storage systems. Providing performance guarantees in d...

Data centers are nowadays highly distributed, possibly over continents, to cope with the huge amounts of data collected these days. To deal with data loss in an environment where hardware failures are very common, researchers have developed new kinds of erasure codes. Erasure coding is a common technique used in all sorts of digital communication, including deep space communication and QR-codes...

Thermal storage is an essential concept within many energy systems. Such storage is generally used in order to smooth out the time lag between the acquisition and the use of energy, for example by using heat water tanks within heating systems. In this work we use a multi-agent system in order to maintain and operate distributed thermal storage among a large group of buildings in a district heat...

Characterizing the exact repair storage-vs-repair bandwidth tradeoff for distributed storage systems remains an open problem for more than four storage nodes. Motivated by the prevalence and practical applicability of linear codes, the exact repair problem when restricted to linear codes is considered. The main result of this paper is a new approach to develop bounds for exact repair distribute...

Distributed storage systems are mainly justified due to the limited amount of storage capacity and improving the reliability through distributing data over multiple storage nodes. On the other hand, it may happen the data is stored in unreliable nodes, while it is desired the end user to have a reliable access to the stored data. So, in an event that a node is damaged, to prevent the system rel...

Cloud storage services and NoSQL systems, which have recently found widespread adoption, typically offer only "Eventual Consistency", a rather weak guarantee covering a broad range of potential data consistency behavior. The degree of actual (in-)consistency as a service quality, however, is always unknown. To avoid cost of opportunity or actual costs, resulting data inconsistencies have to be ...

Distributed or peer-to-peer storage solutions rely on the introduction of redundant data to be fault-tolerant and to achieve high reliability. One way to introduce redundancy is by simple replication. This strategy allows an easy and fast access to data, and a good bandwidth efficiency to repair the missing redundancy when a peer leaves or fails in high churn systems. However, it is known that ...

We present Vivace, a key-value storage system for web applications that span many geographicallydistributed sites. Vivace provides strong consistency and replicates data across sites for access locality and disaster tolerance. Vivace is designed to cope well with network congestion across sites, which occurs because the bandwidth across sites is smaller than within sites. To deal with congestio...