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

Design a android application, As mentioned earlier, the game engine will b...

As mentioned earlier, the game engine will be used as the base of developing the Go game for the Android. This includes improving logic of the game, design good graphics and optim

Explain the various page replacement strategies, Explain the various page r...

Explain the various page replacement strategies. Page replacement-basic scheme with diagram Optimal page replacement LRU page replacement FIFO page replacement LRU

Explain segmentation and paging, Why are segmentation and paging sometimes ...

Why are segmentation and paging sometimes combined into one scheme? Segmentation and paging are often combined in order to improve upon each other. Segmented paging is helpful

define system calls, When a computer is started on, the program that execu...

When a computer is started on, the program that executed first is named the ''operating system.'' It controls pretty much all applications in the computer. This adds who logs in, h

What is thrashing, What is thrashing? It is a method in virtual memory...

What is thrashing? It is a method in virtual memory schemes when the processor spends most of its time swapping pages, rather than implementing instructions. This is because o

Protection scheme in unix, Q. Consider a system that holds 5000 users. Pre...

Q. Consider a system that holds 5000 users. Presume that you want to allow 4990 of these users to be able to access one file. a. How would you denote this protection scheme in

What are the requirements for a swapper to work, The swapper work s on t...

The swapper work s on the biggest scheduling priority. Initially it will look for any sleeping process, if not get then it will see for the ready-to-run process for swapping. Bu

Discuss distributed file system caching, Problem: (a) Discuss Distribut...

Problem: (a) Discuss Distributed File System Caching. (Your discussion should include the goal and architecture of distributed file system caching and the various possible c

Define a program that is in execution is known as, Define a program in exec...

Define a program in execution is known as A program in execution is known as a process

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