alue, P□(5% PMLC, 5% MLC)
When the same number of clients are booting at the same time, the MMNC system which adopts the cooperative client-booting method can have a lower server workload than the previous counterparts which did not. The average booting time of clients is also shorter because the utilization efficiency of the network is higher and the server therefore gains a better robustness.
The above-mentioned MMNC system was highly manageable and provided good multimedia support. The cooperative client-booting method further increased the network utilization efficiency, shortened average client-booting time and enhanced maximum load capability of single server. However, these two systems both relied on the single-server architecture, in which one server supported multiple NC clients simultaneously. Therefore not only the robustness of the whole system was limited by this single server, but also the scalability of the system became a bottleneck. Currently, mirroring technique could be used to improve the whole system's robustness and fault-tolerance and avoid such situation that single server brought down the whole system. Also, more powerful hardware and more efficient running algorithms could be adopted to increase the server's performance and load capability. However, the problem that the load capability of the server is limited mainly by the single-server architecture could be bypassed. In fact, it had been found that in practical applications, one PC server of a common hardware configuration can hardly support more than 100 clients. Requirements analysis of the possible MMNC system application showed that client devices of more than the above mentioned upper limit were required for both large-scale and medium-scale applications of NC system. Although clients could be statically divided and assigned to different servers, there were still problems such as how to make an appropriate static division and how to adjust the division according to changing of users' requirements, due to lack of an integrated framework. Another solution is to use a specific server with luxury hardware configurations to satisfy heavy load needs. However, it could result in a soaring system cost and a really low system price/performance ratio. Therefore, application in MMNC system an integrity and unified multi-server architecture, which enabled multiple PC servers dynamically and transparently serve a large number of clients in the form of clusters, could not only maintain its advantages of low cost, good manageability and well support for various applications, but also acquire better availability, scalability, robustness and a load capability increasing according to the number of server nodes.
Therefore, the invention also provides a self-organizing method for the MMNC server clusters, which provides the whole MMNC system better scalability and robustness. Referring to the drawings, a detailed description of the method is provided as follows.
A cluster of a MMNC system includes all the servers, clients and the relationship between them on a connected network. The server cluster is the set of all the servers in a cluster. At the very beginning of the system, all the servers are in an unavailable status, and belong to none of the clusters. Clients could not be used because of lack of available servers on the same connected network. At this moment, there is no server-server or server-client relationship.
The self-organization means the cluster relationship could be formed among servers and clients spontaneously, and can be adapted dynamically. The self-organized server clusters transparently provide clients with the same services that single-server architecture system could provide, such as services for client-booting (including IP address allocation, OS kernel mirror downloading etc.), customizing and downloading of requested applications, and shared data downloading. However, the clients could not perceive the differences between the multi-server architecture and the single-server architecture.
The heart-beating signal of the server is an 