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

Write a short note on pcb, Write a short note on PCB? Every process is ...

Write a short note on PCB? Every process is represented in the operating system by a process control block also called a task control block. It contains more information regard

Explain the application interaction protocols, Explain the Application Inte...

Explain the Application Interaction Protocols Application interaction protocols are uniquely defined for each program and are used to logically describe the data being passed b

Explain the overlay structured program, Overlay structured program: A p...

Overlay structured program: A program consisting of overlays is referred as overlay structured program in which an overlay is a part of program which has similar load origin as

Bag of tasks, The producer-consumermodel above has a standard human analogy...

The producer-consumermodel above has a standard human analogy of an assembly line. Humans have specialized skills, however, whereas threads running the same program do not need to

What are the different directory structures, What are the different directo...

What are the different directory structures? Explain each type. There are five dissimilar directory structures: 1.      Single level directory 2.      Two level directory

What are tree-structured directories, What are Tree-structured directories ...

What are Tree-structured directories We can generalize the directory structure to a tree of arbitrary height. This permits the user to create their own sub directories and to c

Disk scheduling algorithms-first come, FCFS (First Come, First Served) Per...

FCFS (First Come, First Served) Perform operations in order requested No reordering of work queue No starvation every demand is serviced Poor performance

Operation research, scattered resposibi;ity and authority -necessity of ope...

scattered resposibi;ity and authority -necessity of operation research

What is micro-kernel?, Question 1 What is Micro-kernel? What are the benef...

Question 1 What is Micro-kernel? What are the benefits of Micro-kernel? Question 2 Explain seven state process models used for OS with necessary diagram. Differentiate betwee

GIS, 1. The City of Boston needs to be about 2 acres of green space per 1,0...

1. The City of Boston needs to be about 2 acres of green space per 1,000 persons. You have been hired as the GIS expert by an independent consulting company to determine where the

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