This paper discusses and compares several policies to place replicas in tree networks, subject to server capacity and QoS constraints. The client requests are known beforehand, while the number and location of the servers are to be determined. We study three strategies. The first two strategies assign each client to a unique server while the third allows requests of a client to be processed by ...

The placement of data to maximize the performance and minimize the cost of a computing system is an optimization problem that has been studied extensively in several fields, including distributed databases, storage systems and, more recently, content delivery networks. However, little has been done to compare the various approaches and their applicability to different systems. This paper introd...

Peer-assisted cloud storage systems use the unutilized resources of the clients subscribed to a storage cloud to offload the servers of the cloud. The provider distributes data replicas on the clients instead of replicating on the local infrastructure. These replicas allow the provider to provide a highly available, reliable and cheap service at a reduced cost. In this work we introduce NileSto...

Web users often experience slow document transfers caused by poorly performing servers and overloaded network links. A classical solution to this problem is to replicate documents across the Internet and serve client requests at a nearby replica. Content Delivery Networks (CDNs), such as Akamai, offer such replication services to content providers by offering them a worldwide distributed platfo...

The quantum random energy model provides a mean-field description of the equilibrium spin glass transition. We show that it further exhibits a many-body localization-delocalization (MBLD) transition when viewed as a closed quantum system. The mean-field structure of the model allows an analytically tractable description of the MBLD transition using the forward-scattering approximation and repli...

This paper presents measured probability density functions (pdfs) for the end-to-end latency of two-way remote method invocations from a CORBA client to a replicated CORBA server in a fault-tolerance infrastructure. The infrastructure uses a multicast group-communication protocol based on a logical token-passing ring imposed on a single local-area network. The measurements show that the peaks o...

This paper argues that in a distributed system comprised of storage on multiple servers, you can know where you write the replicas of your data or you can know when the replicas will be written but you can’t know both. Introduction Consider a cluster in which there are a number of simple commodity servers with attached storage and a network connecting the servers. Each server has a noticeable f...

Due to severe performance penalties associated with synchronous replication, there is a significant interest in asynchronous replica management protocols. Lazy protocols currently in use either do not guarantee consistency and serializability as needed by transactional semantics or they impose restrictions on placement of data and which data object can be updated. In this paper we consider an a...

Parisi's formal replica-symmetry-breaking (RSB) scheme for mean-field spin glasses has long been interpreted in terms of many pure states organized ultrametrically. However, the early version of this interpretation, as applied to the short-range Edwards-Anderson model, runs into problems because as shown by Newman and Stein (NS) it does not allow for chaotic size dependence, and predicts non-se...