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

Safety algorithm and resource request algorithm, Safety algorithm : This is...

Safety algorithm : This is to make sure if the system is in safe state or not. It may need an order of m x n2 operation to determine if the state of the system is safe or not.

What inference does recovery in distributed systems, Q. Consider a distrib...

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.

Define a public key encryption system, Define a public key encryption syste...

Define a public key encryption system Allows just the correct receiver to decode the data

What is the concept of an atomic operation, Question: Concurrency and Sync...

Question: Concurrency and Synchronization a) Define the following terms: I. Critical section II. Mutual Exclusion III. Deadlock IV. Starvation. b) Name three methods w

How several bits are there in the logical address, Q. Regard as a logical a...

Q. Regard as a logical address space of eight pages of 1024 words every mapped onto a physical memory of 32 frames. a. How several bits are there in the logical address? b. H

Define system call, Define System Call A system call is a request that ...

Define System Call A system call is a request that is made by any program to the operating system for carrying out tasks - picked from a predefined set - which the said program

Rule a magnetic hard disk, Q. If magnetic hard disks eventually have the s...

Q. If magnetic hard disks eventually have the same cost per gigabyte as do tapes will tapes turn into obsolete or will they still be needed? Describe your answer. Answer: Tap

Illustrate scope of consumer behaviour, Q. Illustrate Scope of Consumer beh...

Q. Illustrate Scope of Consumer behaviour ? Scope of consumer behaviour is extremely wide due to following reasons: >>Ever rising intensifying competition. >>Additional a

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