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

Compare user threads and kernel threads, Compare user threads and kernel th...

Compare user threads and kernel threads. User threads:- User threads are supported above the kernel and are executed by a thread library at the user level. Thread creation

Nachos file system, File System Interface and Implementation The Nachos ...

File System Interface and Implementation The Nachos file system, as distributed, uses a single-level index allocation method for data allocation of files. In the current design,

The key challenges of distributed systems, Question 1 Explain the followin...

Question 1 Explain the following with respect to Resource Management in Distributed Systems- Task assignment Approach Load - Balancing Approach Load - Sharing Approach

Explain medium term scheduling, Medium term scheduling This is componen...

Medium term scheduling This is component of the swapping function. Usually the swapping in decision is based on the need to manage the degree of multiprogramming. At a system t

Kernel mode and user mode function, Q. How does the distinction among kerne...

Q. How does the distinction among kernel mode and user mode function as a rudimentary form of protection (security) system? Answer: The distinction among kernel mode and user m

Perform alpha-beta pruning on the following tree, Perform alpha-beta prunin...

Perform alpha-beta pruning on the following tree. Put an "X" over each node that is pruned. Put the final value next to all other nodes. Indicate which action MAX should take: to B

What are the benefits of multithreaded programming, What are the benefits o...

What are the benefits of multithreaded programming? The advantages of multithreaded programming can be broken down into four main categories: Responsiveness Resourc

Explain multiprocessing operating system, Multiprocessing - An Operating S...

Multiprocessing - An Operating System proficient of utilizing and supporting more than one computer processor. Below are some instances of multiprocessing Operating Systems. Li

Write a note on deadlocks, Write a note on deadlocks. The proper defini...

Write a note on deadlocks. The proper definition of deadlock A set of processes is deadlocked if every process in the set is waiting for an event that only a proces

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