Advantages Of Job Scheduling Strategies

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Scheduling Strategies: The scheduling strategies for tasks differs from scheduling policies as scheduling strategies states how to allocate jobs and which resources should be used in allocation and reallocation for the best possible utilization of computing powers. While scheduling policy dictates the ordering of jobs and requests when rescheduling is done. The task scheduling in a distributed systems differs from scheduling in a single multicore system as a distributed system contain many machines which have their own scheduling policies locally. Therefore there was a need for the distributed systems to have their own scheduling strategies on the top of local schedulers. In this section an insight of different grid scheduling strategies…show more content…
Condor utilizes a centralized scheme based around the ClassAd matchmaker. In the centralized organization, there is only one scheduling controller that is responsible for the system-wide decision making. Such an organization has several advantages including easy management, simple deployment, and the ability to co-allocate resou rces. In a Grid RMS th e disadvantages of this organization su c h as the lack of scalability, lack of fault-tolera nce, and the difficulty in accommodating multiple policies outweigh the advantages. Condor utilizes a centralized scheme based around the ClassAd matchmaker. The traditional and most simple job scheduling strategy uses centralized approach in which there is one central scheduler responsible for the decision making of job allocation and reallocation. This central scheduler makes schedules for all clusters or sites it have in the grid and all entities or machines in the grid are forced to follow the schedule made by grid scheduler. Most of the centralized schedulers uses a greedy strategy with support for priorities. They store the incoming jobs to be processed in a FIFO queue and assign the job to fastest processor that is idle. If some reserved processor is slower than the idle processor, then the scheduler reallocates the job running on slower processor to the faster idle processor, hence preempting or interrupting task on slower machine and reassigning to faster one.…show more content…
In a decentralized organization, tasks execution is distributed among participating clusters of grid and every cluster has its own local scheduler or coordinator and execution machines. Every incoming job is submitted to any of local scheduler, which maintains a queue of tasks to execute. It also listens to requests of external tasks by local schedulers of some other clusters and can accept or decline the execution request. The local schedulers can also implement their own scheduling policies locally to fulfil the needs of its cluster. Hence it allows decentralized organization to implement multi policies and hence achieve site

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