What inference does recovery in distributed systems, Operating System

Assignment Help:

Q. Consider a distributed system with two sites A and B. Consider whether site A can distinguish among the following:

a. B goes down.

b. The link between A and B goes down.

c. B is much overloaded and its response time is 100 times longer than normal.

What inference does your answer have for recovery in distributed systems?

Answer: One technique would be for B to at regular intervals send an I-am-up message to a indicating it is still alive. If A doesn't receive an I-am-up message it can assume either B-or the network link-is down.

Note that an I-am-up message doesn't permit A to distinguish between each type of failure. One technique that permits A better to determine if the network is down is to send an Are-you-up message to B using an exchange route. If it obtains a reply it can determine that indeed the network link is down and that B is up.

If we presume that A knows B is up and is reachable (via the I-am-up mechanism) in addition to that A has some value N that indicates a normal response time A could monitor the response time from B and compare values to N permitting A to determine if B is overloaded or not.

The inferences of both of these techniques are that A could choose another host-say C-in the system if B is either down or unreachable and or overloaded.


Related Discussions:- What inference does recovery in distributed systems

Explain the types of system calls, Explain the Types of System Calls Th...

Explain the Types of System Calls The major types of system calls are like this: a. Process Control: These types of system calls are employed to control the processes.

Write a note on multithreading, Write a note on multithreading. Multith...

Write a note on multithreading. Multithreading is the capability of an operating system to execute different parts of a program called as threads, at the same time. The program

Explain the fork function, Explain the Fork Function Fork function caus...

Explain the Fork Function Fork function causes a new process to be created. The calling progress is duplicated as an exact copy (called the child process) that differs only in

Explain wait for graph, Explain Wait for Graph a. Use a resource alloca...

Explain Wait for Graph a. Use a resource allocation graph to derive a wait-for graph.  b. Wait-for graph acquired by making an edge from p 1 to p 2 iff p 1 is waiting for

Network operating system and a distributed operating system, Problem: (...

Problem: (a) (i) Explain what a single system image is and how it is related to the concept of a distributed operating system? (ii) What are the main differences between a

What is low-level formatting, What is low-level formatting? Before a di...

What is low-level formatting? Before a disk can kept data, it must be required into sectors that the disk controller can read and write. This procedure is called low-level form

Explain the concept of process, Q. Explain the Concept of Process? A pr...

Q. Explain the Concept of Process? A process is sequential program in execution. A process states the basic unit of computation for the computer. Components of process are:

Explain the thread contextual data, Explain the Thread Contextual Data  ...

Explain the Thread Contextual Data  Threads in Net Ware carry additional context as well. Per-thread, stacks, errno, Net Ware Errno, t_errno and others are available to the ap

Fundamental of operating system, An operating system provides the environme...

An operating system provides the environment within that programs are executed. Internally operating systems differ greatly in their makeup because they are organized along many di

MICROKERNEL, ADVANTAGES OF MICROFERNEL IN YSTEM DESIGN?

ADVANTAGES OF MICROFERNEL IN YSTEM DESIGN?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd