scholarly journals A four-phase data replication algorithm for data grid

2015 ◽  
Vol 4 (1) ◽  
pp. 163 ◽  
Author(s):  
Alireza Saleh ◽  
Reza Javidan ◽  
Mohammad Taghi FatehiKhajeh
Keyword(s):  
Large Scale ◽  
Data Replication ◽  
Data Grid ◽  
Data Availability ◽  
Access Time ◽  
File Transfer ◽  
System Availability ◽  
Large Scale Data ◽  
Effective Network ◽  
Average Access Time

<p>Nowadays, scientific applications generate a huge amount of data in terabytes or petabytes. Data grids currently proposed solutions to large scale data management problems including efficient file transfer and replication. Data is typically replicated in a Data Grid to improve the job response time and data availability. A reasonable number and right locations for replicas has become a challenge in the Data Grid. In this paper, a four-phase dynamic data replication algorithm based on Temporal and Geographical locality is proposed. It includes: 1) evaluating and identifying the popular data and triggering a replication operation when the popularity data passes a dynamic threshold; 2) analyzing and modeling the relationship between system availability and the number of replicas, and calculating a suitable number of new replicas; 3) evaluating and identifying the popular data in each site, and placing replicas among them; 4) removing files with least cost of average access time when encountering insufficient space for replication. The algorithm was tested using a grid simulator, OptorSim developed by European Data Grid Projects. The simulation results show that the proposed algorithm has better performance in comparison with other algorithms in terms of job execution time, effective network usage and percentage of storage filled.</p>

scholarly journals Multiobjective Glowworm Swarm Optimization-Based Dynamic Replication Algorithm for Real-Time Distributed Databases

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Saadi Hamad Thalij ◽  
Veli Hakkoymaz
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Distributed Databases ◽  
Data Replication ◽  
Data Availability ◽  
Access Time ◽  
Swarm Optimization ◽  
Dynamic Data ◽  
Glowworm Swarm Optimization ◽  
Dynamic Data Replication

Distributed systems offer resources to be accessed geographically for large-scale data requests of different users. In many cases, replication of the vital data files and storing their replica in multiple locations accessible to the requesting clients is vital in improving the data availability, reliability, security, and reduction of the execution time. It is important that real-time distributed databases maintain the consistency constraints and also guarantee the time constraints required by the client requests. However, when the size of the distributed system increases, the user access time also tends to increase, which in turn increases the vitality of the replica placement. Thus, the primary issues that emerge are deciding upon an optimal replication number and identifying perfect locations to store the replicated data. These open challenges have been considered in this study, which turns to develop a dynamic data replication algorithm for real-time distributed databases using a multiobjective glowworm swarm optimization (MGSO) strategy. The proposed algorithm adapts the random patterns of the read-write requests and employs a dynamic window mechanism for replication. It also models the replica number and placement problem as a multiobjective optimization problem and utilizes MGSO for resolving it. The cost models are presented to ensure the time constraint satisfaction in servicing user requests. The performance of the MGSO dynamic data replication algorithm has been studied using competitive analysis, and the results show the efficiency of the proposed algorithm for the distributed databases.

scholarly journals Efficient Dynamic Replication Algorithm Using Agent for Data Grid

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Priyanka Vashisht ◽  
Rajesh Kumar ◽  
Anju Sharma
Keyword(s):  
Data Replication ◽  
Data Access ◽  
Data Grid ◽  
Data Availability ◽  
Access Time ◽  
Test Bed ◽  
Data Grids ◽  
Dynamic Replication ◽  
Data Files ◽  
Using Data

In data grids scientific and business applications produce huge volume of data which needs to be transferred among the distributed and heterogeneous nodes of data grids. Data replication provides a solution for managing data files efficiently in large grids. The data replication helps in enhancing the data availability which reduces the overall access time of the file. In this paper an algorithm, namely, EDRA using agents for data grid, has been proposed and implemented. EDRA consists of dynamic replication of hierarchical structure taken into account for the selection of best replica. Decision for selecting the best replica is based on scheduling parameters. The scheduling parameters are bandwidth, load gauge, and computing capacity of the node. The scheduling in data grid helps in reducing the data access time. The distribution of the load on the nodes of data grid is done evenly by considering scheduling parameters. EDRA is implemented using data grid simulator, namely, OptorSim. European Data Grid CMS test bed topology is used in this experiment. The simulation results are obtained by comparing BHR, LRU, No Replication, and EDRA. The result shows the efficiency of EDRA algorithm in terms of mean job execution time, network usage, and storage usage of node.

scholarly journals ACCESS TIME OF EMERGENCY VEHICLES UNDER THE CONDITION OF STREET BLOCKAGES AFTER A LARGE EARTHQUAKE

2016 ◽  
Vol III-4/W1 ◽  
pp. 37-44
Author(s):  
N. Hirokawa ◽  
T. Osaragi
Keyword(s):  
Simulation Model ◽  
Large Scale ◽  
Large Earthquake ◽  
Access Time ◽  
Microscopic Simulation ◽  
Property Damage ◽  
Emergency Vehicles ◽  
Fire Stations ◽  
Average Access Time ◽  
Alternative Routes

The previous studies have been carried out on accessibility in daily life. However it is an important issue to improve the accessibility of emergency vehicles after a large earthquake. In this paper, we analyzed the accessibility of firefighters by using a microscopic simulation model immediately after a large earthquake. More specifically, we constructed the simulation model, which describes the property damage, such as collapsed buildings, street blockages, outbreaks of fires, and fire spreading, and the movement of firefighters from fire stations to the locations of fires in a large-scale earthquake. Using this model, we analyzed the influence of the street-blockage on the access time of firefighters. In case streets are blocked according to property damage simulation, the result showed the average access time is more than 10 minutes in the outskirts of the 23 wards of Tokyo, and there are some firefighters arrive over 20 minutes at most. Additionally, we focused on the alternative routes and proposed that volunteers collect information on street blockages to improve the accessibility of firefighters. Finally we demonstrated that access time of firefighters can be reduced to the same level as the case no streets were blocked if 0.3% of residents collected information in 10 minutes.

A Two-Level Fuzzy Value-Based Replica Replacement Algorithm in Data Grids

Fuzzy Systems ◽  
2017 ◽  
pp. 516-539
Author(s):  
Nazanin Saadat ◽  
Amir Masoud Rahmani
Keyword(s):  
Data Grid ◽  
Data Availability ◽  
Distributed Data ◽  
Similar Data ◽  
Replacement Algorithm ◽  
Minimum Latency ◽  
Network Usage ◽  
Effective Network ◽  
And Storage ◽  
Replica Replacement

One of the challenges of data grid is to access widely distributed data fast and efficiently and providing maximum data availability with minimum latency. Data replication is an efficient way used to address this challenge by replicating and storing replicas, making it possible to access similar data in different locations of the data grid and can shorten the time of getting the files. However, as the number and storage size of grid sites is limited and restricted, an optimized and effective replacement algorithm is needed to improve the efficiency of replication. In this paper, the authors propose a novel two-level replacement algorithm which uses Fuzzy Replica Preserving Value Evaluator System (FRPVES) for evaluating the value of each replica. The algorithm was tested using a grid simulator, OptorSim developed by European Data Grid projects. Results from simulation procedure show that the authors' proposed algorithm has better performance in comparison with other algorithms in terms of job execution time, total number of replications and effective network usage.

Towards a New Data Replication Management in Cloud Systems

2019 ◽  
Vol 10 (2) ◽  
pp. 1-20
Author(s):  
Abdenour Lazeb ◽  
Riad Mokadem ◽  
Ghalem Belalem
Keyword(s):  
Large Scale ◽  
Data Replication ◽  
Cloud Provider ◽  
Large Scale Data ◽  
Dynamic Replication ◽  
Replication Strategy ◽  
Multiple Copies ◽  
Cloud Environments ◽  
Real Challenge ◽  
Scale Data

Applications produce huge volumes of data that are distributed on remote and heterogeneous sites. This generates problems related to access and sharing data. As a result, managing data in large-scale environments is a real challenge. In this context, large-scale data management systems often use data replication, a well-known technique that treats generated problems by storing multiple copies of data, called replicas, across multiple nodes. Most of the replication strategies in these environments are difficult to adapt to cloud environments. They aim to achieve the best performance of the system without meeting the important objectives of the cloud provider. This article proposes a new dynamic replication strategy. The proposed algorithm significantly improves provider gain without neglecting customer satisfaction.

scholarly journals Novelty circular neighboring technique using reactive fault tolerance method

2019 ◽  
Vol 9 (6) ◽  
pp. 5211
Author(s):  
Ahmad Shukri Mohd Noor ◽  
Nur Farhah Mat Zian ◽  
Noor Hafhizah Abd Rahim ◽  
Rabiei Mamat ◽  
Wan Nur Amira Wan Azman
Keyword(s):  
Fault Tolerance ◽  
Data Replication ◽  
Data Availability ◽  
Complex Environment ◽  
Tolerance Mechanism ◽  
System Availability ◽  
Replication Technique ◽  
The Right ◽  
Tolerance Method ◽  
Reactive Method

The availability of the data in a distributed system can be increase by implementing fault tolerance mechanism in the system. Reactive method in fault tolerance mechanism deals with restarting the failed services, placing redundant copies of data in multiple nodes across network, in other words data replication and migrating the data for recovery. Even if the idea of data replication is solid, the challenge is to choose the right replication technique that able to provide better data availability as well as consistency that involves read and write operations on the redundant copies. Circular Neighboring Replication (CNR) technique exploits neighboring policy in replicating the data items in the system performs well with regards to lower copies needed to maintain the system availability at the highest. In a performance analysis with existing techniques, results show that CNR improves system availability by average 37% by offering only two replicas needed to maintain data availability and consistency. The study demonstrates the possibility of the proposed technique and the potential of deploying in larger and complex environment.

Grid Computing Based Middleware for Labor and Social Security Data Storage Resources Discovery

2011 ◽  
Vol 148-149 ◽  
pp. 1425-1428
Author(s):  
Jian Yu
Keyword(s):  
Social Security ◽  
Grid Computing ◽  
Data Storage ◽  
Social Insurance ◽  
Large Scale ◽  
Data Grid ◽  
Dynamic Management ◽  
Grid Middleware ◽  
Large Scale Data ◽  
Large Groups

Labor and social security social insurance and employment related to large groups of services. The labor security department of information technology often combined with computational grid computing systems. This paper presents a new kind of data grid middleware for data storage resources discovery and dynamic management in labor and social security resources environment. The architecture of grid storage resources discovery and dynamic management is presented for discovering data storage resources from the different computer organizational structure. The middleware can realize the necessary functions for the ultra large-scale application in data grid environment. It could be applied to the ultra large-scale data storage management in grid computing in next generation labor and social security resources environment.

scholarly journals ACCESS TIME OF EMERGENCY VEHICLES UNDER THE CONDITION OF STREET BLOCKAGES AFTER A LARGE EARTHQUAKE

2016 ◽  
Vol IV-4/W1 ◽  
pp. 37-44 ◽  
Author(s):  
N. Hirokawa ◽  
T. Osaragi
Keyword(s):  
Simulation Model ◽  
Large Scale ◽  
Large Earthquake ◽  
Access Time ◽  
Microscopic Simulation ◽  
Property Damage ◽  
Emergency Vehicles ◽  
Fire Stations ◽  
Average Access Time ◽  
Alternative Routes

The previous studies have been carried out on accessibility in daily life. However it is an important issue to improve the accessibility of emergency vehicles after a large earthquake. In this paper, we analyzed the accessibility of firefighters by using a microscopic simulation model immediately after a large earthquake. More specifically, we constructed the simulation model, which describes the property damage, such as collapsed buildings, street blockages, outbreaks of fires, and fire spreading, and the movement of firefighters from fire stations to the locations of fires in a large-scale earthquake. Using this model, we analyzed the influence of the street-blockage on the access time of firefighters. In case streets are blocked according to property damage simulation, the result showed the average access time is more than 10 minutes in the outskirts of the 23 wards of Tokyo, and there are some firefighters arrive over 20 minutes at most. Additionally, we focused on the alternative routes and proposed that volunteers collect information on street blockages to improve the accessibility of firefighters. Finally we demonstrated that access time of firefighters can be reduced to the same level as the case no streets were blocked if 0.3% of residents collected information in 10 minutes.

scholarly journals Access Weight Replica Consistency Protocol for Large Scale Data Grid

2008 ◽  
Vol 4 (2) ◽  
pp. 103-110
Author(s):  
Mohammed Radi ◽  
Ali Mamat ◽  
M. Mat Deris ◽  
Hamidah Ibrahim ◽  
Subramaniam Shamala
Keyword(s):  
Large Scale ◽  
Data Grid ◽  
Large Scale Data ◽  
Consistency Protocol ◽  
Replica Consistency ◽  
Scale Data
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