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 worst fit algorithm, Worst Fit Algorithm Here we obtain the la...

Worst Fit Algorithm Here we obtain the largest space available for the smallest. Therefore after that process entered there will be much more space remaining. In this space we

What is indexed allocation, What is indexed allocation? Every file has ...

What is indexed allocation? Every file has its own block of pointers to the sectors of the file.

Need of shift alteration in critical section problem?, Explain with an exam...

Explain with an example the need of Shift Alteration in critical section problem? Consider processes P i and P j and consider the algorithm for P i and P j .

Define busy waiting and spinlock, Define busy waiting and spinlock. Whe...

Define busy waiting and spinlock. When a process is in its significant section, any other process that tries to enter its critical section must loop continuously in the entry c

Explain single partition allocation., Operating Systems 1. Explain sing...

Operating Systems 1. Explain single Partition Allocation and Multiple Partition Allocation. 2. What do you mean by PCB? What useful information is available in PCB? 3. De

integrator circuit, Referring to Figure below, discuss how you would alter...

Referring to Figure below, discuss how you would alter the circuit to obtain: 1. a straightforward amplifier with gain 1, 2. a straightforward amplifier with gain 10, 3. a

Is the internet a lan or else a wan, Q. Is the Internet a LAN or else a WAN...

Q. Is the Internet a LAN or else a WAN? Answer: The Internet is a WAN as the a variety of computers are located at geographically different places and are connected by long-dis

Explain what type of group scope you will use, Question: (a) The actual...

Question: (a) The actual use and scope groups depend on the mode in which a domain is running. There are two domain modes in which you can run a Windows 2000 domain. List and d

What problems arise if the directory is a general graph, What problems aris...

What problems arise if the directory structure is a general graph? Searching for a particular file may result in searching the similar directory many times. Deletion of the fil

What are the operations of processes, What are the operations of processes?...

What are the operations of processes? Process creation A process may create several new processes. The creating process is called as parent process, where as the new proce

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