Learn More
Erasure correcting codes are widely used to ensure data persistence in distributed storage systems. This paper addresses the simultaneous repair of multiple failure in such codes. We go beyond existing work (i.e., regenerating codes by Dimakis et al.) and propose coordinated regenerating codes allowing devices to coordinate during simultaneous repairs thus(More)
The explosion of the amount of data stored in cloud systems calls for more efficient paradigms for redundancy. While replication is widely used to ensure data availability, erasure correcting codes provide a much better trade-off between storage and availability. Regenerating codes are good candidates for they also offer low repair costs in term of network(More)
The availability of end devices of peer-to-peer storage and backup systems has been shown critical for usability and for system reliability in practice. This has led to the adoption of hybrid architectures composed of both peers and servers. Such architectures mask the instability of peers thus approaching the performances of client-server systems while(More)
Distributed storage systems rely heavily on redundancy to ensure data availability as well as durability. In networked systems subject to intermittent node unavailability, the level of redundancy introduced in the system should be minimized and maintained upon failures. Repairs are well-known to be extremely bandwidth-consuming and it has been shown that,(More)
Modern storage systems now typically combine plain replication and erasure codes to reliably store large amount of data in datacenters. Plain replication allows a fast access to popular data, while erasure codes, <i>e.g</i>., Reed-Solomon codes, provide a storage-efficient alternative for archiving less popular data. Although erasure codes are now(More)
Monitoring a system is the ability of collecting and analyzing relevant information provided by the monitored devices so as to be continuously aware of the system state. However, the ever growing complexity and scale of systems makes both real time monitoring and fault detection a quite tedious task. Thus the usually adopted option is to focus solely on a(More)
Pure megakaryocytic colonies, megakaryocytic-erythroid colonies and mixed hemopoietic colonies can be cultured from human bone marrow under appropriate culture conditions. Human plasma and mercaptoethanol support the growth for these different types of hemopoietic colonies. However, the addition of medium conditioned by leucocytes in the presence of(More)
With the emergence of online platforms for (social) sharing, collaboration and backing up, mobile users generate ever-increasing amounts of digital data, such as documents, photos, and videos, which they upload while on the go. Cellular Internet connectivity (e.g., 3G/4G) enables mobile users to upload their data but drains the battery of their devices and(More)
In this paper, we study cache policies for cloud-based caching. Cloud-based caching uses cloud storage services such as Amazon S3 as a cache for data items that would have been recomputed otherwise. Cloud-based caching departs from classical caching: cloud resources are potentially infinite and only paid when used, while classical caching relies on a fixed(More)