A cluster is a parallel or distributed system consisting of independent computers that cooperate as a single system. In the case Server, Cluster consists of two types of participant's dispatchers and servers. The goal of a cluster is to allow distributing of the computing load over the several machines participating in it. These machines communicate with the dispatchers and with each other in order to provide better, faster and more reliable service to the client. The idea of clusters is that the machines in it represent one unit and clients perceive the cluster as a single entity, not as a group, for clients the IP address of the dispatcher is the IP address of the whole cluster. When connected in a cluster, servers are still physically separated as different machines. The participants in the cluster share disk access and resources that manage data, but they do not share memory or processors.
[...] IT managers need to have a complete antivirus security solution, but with the numerous virus outbreaks that have occurred recently, it is clear that they must implement security systems that give them the control and the ability to respond in a major disaster situation. The gateway has become the most valibel point for Internet based threats. But the gateway serves mission critical business functions. So IT managers have several key concerns about implementing such a gateway solution. Stability: Is the antivirus solution going to work smoothly with the other hardware, software, firewall and network systems? [...]
[...] Usually requests do not pass through all of these steps but skip some of the steps and go directly to a next step. b. The picture shows only one server besides the dispatcher. The reason is to simplify the presentation of processing request in the system, no matter on which of the many servers in the cluster. c. The path for delivering the results of processing is along the same route but in reverse order, i.e. step etc. and because of that it is not presented separately. [...]
[...] Desktop systems are constantly changing with the installation of new software, software updates, and configuration changes. These can interfere with the antivirus software's ability to detect viruses blocking portions of the software that would otherwise detect a particular threat. Most often the virus pattern files the database, the antivirus software uses to identify virus update mechanism has been interfered. Figure Business Internet Users' Security Fears viruses Unauth information Data Dos Trojan Manip Theft of illegal Source: Information Week Global Information Security Survey of 2700 Security Professionals, July In addition to provide centralized management, these solutions incorporate a number of techniques that enable IT managers to verify the effectiveness of each desktop systems' antivirus installation, force updates, block user access to the antivirus software and perform other functions to insure that each desktop system is current and running correctly. [...]
[...] Each of the servers in the cluster Communicate with all other servers and dispatchers, as in the picture shows. Cluster Configurations: Cluster solutions depend on the goals set for a particular system. Complexity of applications expects number of requests, available hardware etc its administrator must choose how to configure the cluster. The recommended cluster configurations for application servers can be divided into two groups with more than one dispatchers. the presence of at least one dispatcher and one server is necessary in order a cluster to be set. [...]
[...] This could be any external database, drivers for which it is supported by Oracle, SAP-DB, etc. This is the last stage in processing the request by an application server. The Security Threat: The “Internet has arrived, bringing free flowing information to people and businesses throughout the world. And while it has unleashed new business, education, research, and communication opportunities, it has also introduced an explosion of new security threats. Many recent attacks have received worldwide attention including the Melissa virus, Love Letter, Bubble Boy, and numerous Denial of Service (DoS) attacks. [...]
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