In this paper I will be discussing the issue of failures in a distributed system, and to understand the different failures I will write about four failures that occur in and affect a distributed system. Also, I will be discussing and writing about how to isolate and fix two out of the four failure that can occur in the distributed system. In a distributed system nothing is set in stone or perfect, so there are some issues that can arise, and the issues that arise are the failures that can occur in these distributed systems. The failure that can occur are Fail-Stop, Network Failure, Timing Failure, and Byzantine Failures; each of which I will discuss separately. The first of the four failures in the distributed system is Fail-Stop and this is when a halting failure occurs with a type of notification to other components, and this can be when a network file server is in the process of telling its clients it is about to stop executing, and in the process the internal state and the contents connected to the volatile storage can be lost. The second type of failure in a distributed system is network failure, and this can keep processors from being able to communicate with one another.
One of Two problems that come up are one way link and which can lead to problems such as the processors slowing down, this can cause one processor not being able to receive messages from the other processor. The second problem that arises is Network partition and occurs when the connecting line of two sections of the network fail, and it can causes a group of two processors to be able to communicate with one another but not with another group of two processors; this can lead to the two groups of processed downloading a file in different ways leading to the file inconsistent among all processors. The Third type of failure in a distributed system is Timing Failure, is the process or part of one that fails to meet its limit set for executing the process, message, clock drift rate, and clock skew on time. The timing failure causes components to respond with the correct value that is outside the specific interval meaning that it is too soon, or too late. Also overloaded processors can be hit with excessive delays even if the correct values are produced, and most timing failures are only in systems which have timing constraints and computations. The Fourth type of failure in distributed systems is Byzantine Failures occur when or during an execution of an algorithm, and when this failure occurs it can cause the system to respond in an unpredictable way by processing a request in the incorrect way, and corrupting local state in addition to sending an inconsistent response to request, and in a way failing to even receive the request. This can occur when an output of one function happens to be the input of another it causes small round off errors in the first function that could then lead to larger errors in the second function. Out of the four failures that can occur in a distributed system two of them can also occur or be in a centralized system, and the failures are Fail-Stop and Network Failure.
I would assume that these two failures will fault the same way in a centralized system as they do in the distributed system. Of the two out of four failures that can occur in a distributed system the first of which to isolate and fix is network failure, this can be done by spoofing the network. Using the spoofing technique a probe can be sent down paths to find if the failures are on a forward path or reverse path. The way the network failures can be addressed and fixed are by using a network failure detection and recovery in a two-node by using windows server 2000 cluster that runs a sophisticated algorithm which can detect available network interfaces along with the plug and play function to detect disconnected cables used to connect the network, as well as connectivity issues between the network adapter and the hub or switch. Using windows server 2000 cluster can help detect network failures and lead to resolving them. The second out of the four failures in distributed system is the Byzantine Failure and the way to isolate and fix the failure is by using a solution called Practical Byzantine Fault Tolerance which is an algorithm that can provide high performance Byzantine state machine replication, allowing for processing thousands of request a second with the use of sub-millisecond increase in latency. Another way to help isolate and fix Byzantine Failures is using a redundant system that can use or migrate of mask the effect of a limited amount of faults through redundancy, this can lead to the detection of faulty nodes and identifying and isolating them before they can harm from failure. When it comes to dealing with a distributed system, an organization can run into failures, four of which were described in this paper and they are; Fail-Stop, Network Failure, Timing Failure, and Byzantine Failure but this also includes others that were not discussed. Never the less, these failures can and will occur, it is up to the organization of company running their system to identity these failure risk, isolate them if they are found, and of course they action to guard against and fix issues of failures so it will not cause irreversible damage and harm that can lead to loss of information and time. These failures are inevitable but knowing about them and how to use fault tolerant protocols will indeed safeguard a distributed system