The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Cloud SQL Server is a relational database system designed to scale-out to cloud computing workloads. It uses Microsoft SQL Server as its core. To scale out, it uses a partitioned database on a shared-nothing system architecture. Transactions are constrained to execute on one partition, to avoid the need for two-phase commit. The database is replicated for high availability using a custom primary-copy...
Replication is a well-established approach to increasing database availability. Many database replication protocols have been proposed for the crash-stop failure model, in which servers fail silently. Fewer database replication protocols have been proposed for the byzantine failure model, in which servers may fail arbitrarily. This paper considers deferred update replication, a popular database replication...
The current implementations of cloud environment do not have suitable mechanism through which services can be managed to make use of cloud resources. The services in these environments can passively serve users' request only. If a service receives more requests than it can handle in a certain time period, it is subject to malfunctioning. This paper proposes a new approach to service replications that...
Abstract-A probabilistic data stream S is defined as a sequence of uncertain tuples <;ti, pi >;, i = 1...∞, with the semantics that element ti occurs in the stream with probability pi ϵ (0, 1). Thus each distinct element t, which occurs in tuples of S, has an existential probability based on the tuples: <; ti = t, pi >; ϵ S. Existing duplicate...
Data grids support distributed data-intensive applications that need to access massive datasets stored around the world. Ensuring efficient access to such datasets is hindered by the high latencies of wide-area networks. To speed up access, files can be replicated so a user can access a nearby replica. Replication also provides improved availability, decreased bandwidth use, increased fault tolerance,...
In distributed Geographic Information System (GIS), spatial data has multi-source, heterogeneous characteristics, so there are data inconsistencies between nodes. Although there were many approaches about data consistency, a single strategy can not meet the replicas of spatial data which has large volume and complex topology. For the particularity of spatial data, through data partitioning, the paper...
In the e-commerce environment, the protection of users' privacy from a server was not considered feasible until the private information retrieval (PIR) problem was stated and solved. A PIR scheme allows a user to retrieve a data item from an online database while hiding the identity of the item from a database server. In 1995, Chor et al. stated private information retrieval (PIR) problem and proposed...
As XML document is distributed across the web, it can be considered like a distributed repository of XML documents and is subjected to distribution design. However, there is no adequate works on XML document distribution design. To address the shortcomings in XML document fragmentation design, in this work, we have focused on the vertical fragmentation design of the XML documents. Two fragmentation...
LDAP Multi-Master Technique is a replication approach using Syncrepl to replicate data to multiple servers. As the specialized database optimized for read access, the directory is used to represent heterogeneous entities in directory information tree (DIT). Compared with existing Sync replication models, the directory template replication model based on query templates proposed in this paper only...
Over the Internet today, computing and communications environments are more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. Peer-to-Peer network overlays provide a good substrate for creating large-scale data sharing, content distribution and application-level multicast applications. We present DistHash, a P2P overlay network designed...
Data grid, which provides the capability to store the mass data, has become one of the hottest topics in distributed storage research domains. However, the limited capacity of local storage devices and the high latency of network have become the bottlenecks for efficiently accessing the files in the data grids. These problems can be solved through introducing a replication strategy by which the overall...
The best replica selection problem is one of the important aspects of data management strategy of data grid infrastructure. Recently, rough set theory has emerged as a powerful tool for problems that require making optimal choice amongst a large enumerated set of options. In this paper, we propose a new replica selection strategy using a grey-based rough set approach. Here first the rough set theory...
Aggregating the capacity and bandwidth of the commodity disks in the nodes of a cluster provides cost effective and high performance storage systems. Nevertheless, this strategy could be a feasible approach only if the mean time to failure of disks and nodes is faced. The number of failures increases with the nodes and it is especially important in parallel file systems, like PVFS, because having...
In this paper, we investigate a decentralized approach to timestamping transactions in a replicated database, under partial replication in Peer-To-Peer (P2P) environments. In order to solve problems of concurrent updates and node failures, we propose an architecture based on quorums, this architecture allows assigning a unique timestamp to each distributed transaction, to select the servers replicas...
Partial Replicas have been used to parallelize access to regions of large spatial data sets on geographically distributed machines, saving network bandwidth and improving data availability. In this paper, we present the Globus Toolkit R-tree, (GTR-tree) to efficiently select partial replicas using the Globus Toolkit Replica Location Service (RLS) middleware. First, the limitations inherent in the...
The technology of multimedia Content Delivery Network (CDN) is to build some replica servers in the network. The origin server replicates some multimedia contents to these replica servers in order to reduce the loading of the origin server and to reduce the utilization of bandwidth. The client issues a request to the most appropriate replica server instead of the origin server, which can provide the...
We propose a consistency model for a data store in the Cloud and develop a framework towards the goal of deploying Database as a Service over the Cloud. This includes consistency across the data partitions and consistency of any replicas that exist across different nodes in the system. We target applications which need stronger consistency guarantees than the applications currently supported by the...
High-performance I/O is a key requirement for many of today's critical computational science applications, and parallel file systems are being driven to progressively larger scales to keep pace with demand. One cost-effective way to meet this demand is through the deployment of commodity storage hardware in conjunction with file systems that provide software resiliency. This requires a re-evaluation...
In cluster file systems, the metadata management is critical to the whole system. Past researches mainly focus on journaling which alone is not enough to provide high-available metadata service. Some others try to use replication, but the extra latency accompanied is a main problem. To guarantee both availability and efficiency, we propose a mechanism for building highly available metadata servers...
Replication is a widely used method to protect large-scale data storage systems from data loss when storage nodes fail. It is well known that the placement of replicas of the different data blocks across the nodes affects the time to rebuild. Several systems described in the literature are designed based on the premise that minimizing the rebuild times maximizes the system reliability. Our results...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.