scholarly journals Distributed Application Checkpointing for Replicated State Machines

2021 ◽  
Vol 22 (1) ◽  
pp. 67-79
Author(s):  
Özdinç Çelikel ◽  
Tolga Ovatman
Keyword(s):  
Fault Tolerance ◽  
Recovery Time ◽  
State Machines ◽  
Cloud Environment ◽  
Memory Consumption ◽  
Local Cluster ◽  
Distributed Application ◽  
Recovery Mechanism ◽  
Single Instance ◽  
Different Levels

Application checkpointing is a widely used recovery mechanism that consists of saving an application's state periodically to be used in case of a failure. In this study we investigate the utilisation of distributed checkpointing for replicated state machines. Conventionally, for replicated state machines, checkpointing information is stored in a replicated way in each of the replicas or separately in a single instance. Applying distributed checkpointing provides a means to adjust the level of fault tolerance of the checkpointing approach by giving away from recovery time. We use a local cluster and cloud environment to examine the effects of distributed checkpointing in a simple state machine example and compare the results with conventional approaches. As expected, distributed checkpointing gains from memory consumption and utilise different levels of fault tolerance while performing worse in terms of recovery time.

A Review on Load Balancing Model Using Best Partition Technique

2017 ◽  
Vol 7 (8) ◽  
pp. 284
Author(s):  
M. Chaitanya ◽  
K. Durga Charan
Keyword(s):  
Cloud Computing ◽  
Fault Tolerance ◽  
Load Balancing ◽  
Load Balance ◽  
Large Impact ◽  
Cloud Environment ◽  
Public Cloud ◽  
The Public ◽  
Partition Technique ◽  
Textual Content

Load balancing makes cloud computing greater knowledgeable and could increase client pleasure. At reward cloud computing is among the all most systems which offer garage of expertise in very lowers charge and available all the time over the net. However, it has extra vital hassle like security, load administration and fault tolerance. Load balancing inside the cloud computing surroundings has a large impact at the presentation. The set of regulations relates the sport idea to the load balancing manner to amplify the abilties in the public cloud environment. This textual content pronounces an extended load balance mannequin for the majority cloud concentrated on the cloud segregating proposal with a swap mechanism to select specific strategies for great occasions.

Cloud Monitoring

2012 ◽  
pp. 97-116
Author(s):  
Peer Hasselmeyer ◽  
Gregory Katsaros ◽  
Bastian Koller ◽  
Philipp Wieder
Keyword(s):  
State Of The Art ◽  
The State ◽  
Cloud Environment ◽  
State Health ◽  
Cloud Monitoring ◽  
Cloud Environments ◽  
And Performance ◽  
Cloud Infrastructures ◽  
Different Levels ◽  
The Way

The management of the entire service landscape comprising a Cloud environment is a complex and challenging venture. There, one task of utmost importance, is the generation and processing of information about the state, health, and performance of the various services and IT components, something which is generally referred to as monitoring. Such information is the foundation for proper assessment and management of the whole Cloud. This chapter pursues two objectives: first, to provide an overview of monitoring in Cloud environments and, second, to propose a solution for interoperable and vendor-independent Cloud monitoring. Along the way, the authors motivate the necessity of monitoring at the different levels of Cloud infrastructures, introduce selected state-of-the-art, and extract requirements for Cloud monitoring. Based on these requirements, the following sections depict a Cloud monitoring solution and describe current developments towards interoperable, open, and extensible Cloud monitoring frameworks.

Achieving Cloud Security Using a Third Party Auditor and Preserving Privacy for Shared Data Over a Public Cloud

2021 ◽  
pp. 1371-1391
Author(s):  
Vitthal Sadashiv Gutte ◽  
Sita Devulapalli
Keyword(s):  
Cloud Security ◽  
Third Party ◽  
Security Model ◽  
Cloud Environment ◽  
Public Cloud ◽  
Shared Data ◽  
Metadata File ◽  
Efficient Mechanisms ◽  
Different Levels ◽  
Access Security

Correctness of data and efficient mechanisms for data security, while transferring the file to and from Cloud, are of paramount importance in today's cloud-centric processing. A mechanism for correctness and efficient transfer of data is proposed in this article. While processing users request data, a set of attributes are defined and checked. States with attributes at different levels are defined to prevent unauthorized access. Security is provided while storing the data using a chunk generation algorithm and verification of chunks using lightweight Third-Party Auditor (TPA). TPA uses digital signatures to verify user's data that are generated by RSA with MD5 algorithms. The metadata file of generated chunks is encrypted using a modified AES algorithm. The proposed method prevents unauthorized users from accessing the data in the cloud environment, in addition to maintaining data integrity. Results of the proposed cloud security model implementation are discussed.

Modularity and Complex Adaptive Systems

2008 ◽  
pp. 75-104
Author(s):  
David Cornforth ◽  
David G. Green
Keyword(s):  
Fault Tolerance ◽  
Complex Systems ◽  
Long Range ◽  
Complex Adaptive Systems ◽  
Adaptive Systems ◽  
Single Unit ◽  
Phase Changes ◽  
Critical Phase ◽  
Complex Adaptive ◽  
Different Levels

Modularity is ubiquitous in complex adaptive systems. Modules are clusters of components that interact with their environment as a single unit. They provide the most widespread means of coping with complexity, in both natural and artificial systems. When modules occur at several different levels, they form a hierarchy. The effects of modules and hierarchies can be understood using network theory, which makes predictions about certain properties of systems such as the effects of critical phase changes in connectivity. Modular and hierarchic structures simplify complex systems by reducing long-range connections, thus constraining groups of components to act as a single component. In both plants and animals, the organisation of development includes modules, such as branches and organs. In artificial systems, modularity is used to simplify design, provide fault tolerance, and solve difficult problems by decomposition.

scholarly journals Area-Efficient Differential Fault Tolerance Encoding for Finite State Machines

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1110
Author(s):  
Jiwoon Park ◽  
Hoyoung Yoo
Keyword(s):  
Fault Tolerance ◽  
Integrated Circuits ◽  
Finite State Machines ◽  
Digital Circuit ◽  
State Machines ◽  
Information Redundancy ◽  
Area Efficiency ◽  
Time Redundancy ◽  
Finite State ◽  
Scale Down

A differential fault tolerance encoding is presented for finite state machines (FSMs) to improve their area efficiency. As the manufacturing technology for semiconductors continues to scale down, the probability of the occurrence of unexpected faults in integrated circuits has been increasing. Because an FSM controls an entire digital circuit, the faults in FSMs should be carefully addressed. Whereas the previous encoding applies a fault tolerance scheme to all the states in an FSM, the proposed encoding applies a fault tolerance scheme to only specific states depending on their importance. Compared with the previous complete fault tolerance encoding, the proposed encoding provides a comparable failure probability with a small hardware by applying the fault tolerance scheme differently to each state. The proposed method improves the area efficiency by 36.1%, 43.8%, 49.2%, and 74.6% compared with that by the non-fault tolerance, previous hardware redundancy, information redundancy, and time redundancy methods, respectively. Consequently, the proposed method can provide a flexible solution by applying the fault tolerance differently depending on the importance of the states.

scholarly journals A Study on Factors Contributing to Efficiency of Scheduling Algorithms in a Cloud Computing Environment; Overview of Several Algorithms

2015 ◽  
Vol 37 ◽  
pp. 427
Author(s):  
Minoo Soltanshahi ◽  
Aliakbar Niknafs
Keyword(s):  
Cloud Computing ◽  
Fault Tolerance ◽  
Efficient Algorithm ◽  
System Performance ◽  
Scheduling Algorithms ◽  
Cloud Environment ◽  
Computing Environment ◽  
Shared Resources ◽  
Cloud Computing Environment ◽  
Tremendous Impact

Cloud computing is the latest distributed technology providing a rich environment of dynamically shared resources through virtualization, which can fulfill the requirements of users by allocating resources to programs. Any program in a cloud environment is delivered by workflows which are a series of interlinked tasks to accomplish a goal. One of the most important tasks in cloud computing is correct mapping of tasks onto resources. It is essential to schedule processes in distributed systems such as cloud, since it leaves a tremendous impact on the system performance. This is done by scheduling algorithms. Therefore, it is crucial to present and adopt an efficient algorithm in the cloud environment. This article attempted to examine the parameters effective in the efficiency of scheduling algorithms including deadline, cost constraint, balanced loading, power consumption and fault tolerance. Additionally, the performances of several algorithms were briefly discussed.

scholarly journals Potential use of dexmedetomidine for different levels of sedation, analgesia and anaesthesia in dogs

2013 ◽  
Vol 58 (No. 2) ◽  
pp. 87-95 ◽  
Author(s):  
Amarpal ◽  
RA Ahmad ◽  
P. Kinjavdekar ◽  
HP Aithal ◽  
AM Pawde ◽  
...  
Keyword(s):  
Heart Rate ◽  
Recovery Time ◽  
Deep Sedation ◽  
Muscle Relaxation ◽  
Complete Recovery ◽  
Group Iii ◽  
Group I ◽  
Righting Reflex ◽  
Sedation And Analgesia ◽  
Different Levels

A combination of drugs may be preferred over the use of a single agent to induce deep sedation. A synergistic interaction between the drugs reduces the dose requirements of the drugs thereby minimising the unwanted side effects associated with each drug and improving recovery. The present study was undertaken to evaluate the suitability of dexmedetomidine and dexmedetomidine in combination with midazolam-fentanyl or midazolam-fentanyl-ketamine for different levels of sedation, analgesia and anaesthesia in dogs. In a prospective, blinded, randomised clinical trial, 12 mixed breed dogs were divided into three groups. Animals of Group I were injected with dexmedetomidine 20 μg/kg. Animals of Group II received 20 μg/kg dexmedetomidine + 0.2 mg/kg midazolam + 4 μg/kg fentanyl and animals of Group III were administered with 20 μg/kg dexmedetomidine + 0.2 mg/kg midazolam + 4 μg/kg fentanyl + 10 mg/kgketamine. All the drugs were given simultaneously via the intramuscular route. Jaw relaxation, palpebral reflex, pedal reflex and response to intubation were recorded and graded on a numerical scale. Values of heart rate, respiratory rate, rectal temperature and mean arterial pressure were recorded at baseline and then at predetermined intervals up to 120 min. Onset of sedation time, onset of recumbency time, time to return of righting reflex, standing recovery time and complete recovery time were recorded. Maximal muscle relaxation, sedation and analgesia were observed in animals of Group III, which was followed in decreasing order by Groups II and I. Heart rate decreased significantly (P < 0.05) after administration of drugs in Groups I and II but a significant (P < 0.05) increase was recorded in Group III. Respiratory rate decreased significantly (P < 0.05) in all the groups. Rectal temperature decreased non-significantly in all the groups. Mean arterial pressure initially increased significantly (P < 0.01) in Groups I and III followed by a decrease in Group I, but in Group III it remained above the base line. In Group II, MAP decreased throughout the study period. Onset of sedation time and onset of recumbency time were significantly (P < 0.05) shorter in Group III as compared to Group I. Time to return of righting reflex, standing recovery time and complete recovery time did not differ significantly between the groups. It is concluded that dexmedetomidine provides a reliable moderate sedation and analgesia. Addition of midazolam and fentanyl enhances sedation, analgesia and muscle relaxation induced by dexmedetomidine. Addition of ketamine produced deep sedation and complete anaesthesia with lesser cardiopulmonary depression. Thus, dexmedetomidine can be used safely in combination with midazolam, fentanyl and ketamine for different levels of sedation, analgesia and anaesthesia in dogs.  

Improved Checkpoint Using the Effective Management of I/O in a Cloud Environment

2019 ◽  
pp. 219-233
Author(s):  
Bakhta Meroufel ◽  
Ghalem Belalem
Keyword(s):  
Fault Tolerance ◽  
Execution Time ◽  
Large Scale ◽  
Fault Tolerant ◽  
Experimental Results ◽  
Cloud Environment ◽  
Large Scale Systems ◽  
Major Disadvantage ◽  
Reliability And Robustness ◽  
Effective Use

One of the most important points for more effective use in the environment of cloud is undoubtedly the study of reliability and robustness of services related to this environment. In this case, fault tolerance is necessary to ensure that reliability and reduce the SLA violation. Checkpointing is a popular fault tolerance technique in large-scale systems. However, its major disadvantage is the overhead caused by the storage time of checkpointing files, which increases the execution time and minimizes the possibility to meet the desired deadlines. In this chapter, the authors propose a checkpointing strategy with lightweight storage. The storage is provided by creating a virtual topology VRbIO and the use of an intelligent and fault tolerant I/O technique CSDS (collective and selective data sieving). The proposal is executed by active and reactive agents and it solves many problems of checkpointing with standard I/O. To evaluate the approach, the authors compare it with a checkpointing with ROMIO as I/O strategy. Experimental results show the effectiveness and reliability of the proposed approach.

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