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Lab Meeting. Papers Reviewed:. 10 th December, 2013. 1. Fault tolerant workflow scheduling. Primary Issue : Scheduling workflows in a cloud environment, with deadlines, is a complex problem
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Lab Meeting Papers Reviewed: 10th December, 2013
1 Fault tolerant workflow scheduling • Primary Issue : • Scheduling workflows in a cloud environment, with deadlines, is a complex problem • Issues of shared resources, time to release, resource availability, access control during execution, failures, etc. • The main goal is to schedule workflows and execute these workflows within the deadline in-spite of many failures that occur in the environment. • Solution: • Use of replication and resubmission of tasks based on priority of task. • Need to avoid resource wastages • Heuristic metric finds trade-off between replication and resubmission factors without the need for history data 1. Fault tolerant workflow scheduling based on replication and resubmission of tasks in Cloud Computing. Jayadivya et. al.
1 Results Ratio of success rate and resource usage Failure Probability 1. Fault tolerant workflow scheduling based on replication and resubmission of tasks in Cloud Computing. Jayadivya et. al.
1 My Observations • Difficult to understand the relevance of the deadline to the success or failure curves • Failure probabilities for ‘with replication’ would be expected to be much better • Surprising result is Performance Comparison are similar – this is probably due to heuristic metric – which is not discussed in detail. • The mean number of replications necessary to achieve results is not specified 1. Fault tolerant workflow scheduling based on replication and resubmission of tasks in Cloud Computing. Jayadivya et. al.
2 Prediction of Remaining Service Execution Time • Primary Benefits: • Dynamic Process Tracking requires predicted remaining duration • It also assists scheduling of resources • It provides feedback to the client • Present State • Present methods update predictions on event arrival and subtract elapsed time • New Approach: • Also consider expected events that have not occurred • Prediction approach based on PN formalism so that concurrency can be modelled 2. Prediction of remaining service execution time using stochastic PN with arbitrary firing delays. Andreas Rogge-Solti et. al.
1 My Observations • Empirical Models are not use • Requires immediate notification of event • Simulations assume a stable state • In a real-time system this may not be feasible
Thank you…. QUESTIONS