• Savleen Kalra
• Sh. Rajeev Bedi
• Dr. S.K.Gupta

Most of fault tolerant strategies researched over rely on hardware or time redundancy. The techniques are used to mask faults. Time redundancy or replication indicates re-execution of failed component after failure is detected. The result can further be optimizing by the use of checkpoints. This strategy however consumes more time or in other words significant delay is introduced during the operation of fault tolerance. In many mission critical applications hardware redundancy is employed. This approach uses process replication to achieve fault tolerance. Both the approaches have drawbacks. System engineer hence is in dilemma in terms of approach to follow for fault tolerance. Shadow computing is the solution to dilemma which provides dynamic execution. Parameterized trade off between hardware and time redundancy is provided to ensure fault tolerance. This paper provides survey of time redundant, hardware redundant and shadow replication mechanism along with comparison of each.

Fault Tolerance, hardware, time redundancy, shadow replication

"Comparative Study of Fault tolerant Strategy in Cloud", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 5, page no.65-70, May-2019, Available :http://www.jetir.org/papers/JETIR1905112.pdf

"Comparative Study of Fault tolerant Strategy in Cloud", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 5, page no. pp65-70, May-2019, Available at : http://www.jetir.org/papers/JETIR1905112.pdf