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 about time sharing systems, Q. Explain about Time Sharing Systems? ...

Q. Explain about Time Sharing Systems? Time Sharing Systems Multi-programmed batched systems provide an environment where various system resources (for illustration CP

Define process? what is meant by state of a process?, Define process? What ...

Define process? What is meant by state of a process? Process is a program in implementation. A process in general includes the process stack, which consists temporary data and

What are the deadlock prevention methodologies?, What are the deadlock p r...

What are the deadlock p revention methodologies? a.       Necessitate that processes request all resources before starting - if cannot be granted don't run. b.      Process

Semaphores, Synchronization can be achieved by means other than locks and c...

Synchronization can be achieved by means other than locks and condition variables. One alternative is semaphores. A semaphore is used to regulate traf?c in a critical section. A se

What are the system components of an operating system, What are the system ...

What are the system components of an operating system and explain them? a) Process management b) Main-memory management c) I/O management d) File management e) Seco

Briefly explain about file system implementation, Briefly explain about fil...

Briefly explain about file system implementation? Several on-disk and in-memory structures are used to execute a file system. On disk, the file system may have information abou

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