Quick to learn the related knowledge of cluster and dual-server hot backup
High availability cluster, called HA Cluster, is a server cluster technology for the purpose of reducing service downtime. In short, cluster is a group of computers. As a whole, they provide users with a group of network resources. Every computer is called a cluster node. What is an ideal cluster? For our users, it is a system rather than a number of computers, they will never realize the nodes at the bottom of cluster system, and the administrator of cluster system could add or delete nodes randomly. High Availability Cluster is not used to protect business data. It is a protection of user's business application with providing continuous service to the outside, and minimizing business effects caused by software/hardware/human failure.
The so-called dual-server hot backup could be regarded as the smallest unit of cluster. The central server is installed into two servers as a backup. When one of the running servers fails to start, another backup server will automatically activate and run, which ensure that the entire network application system is under normal operation. The mechanism of dual-server hot backup is that it provides automatic restoration capabilities.
With the growth of global economy, the rely on the IT systems from a variety of organizaitons in all over the world are growing, e-commerce makes continuous business with 24 hours, seven days a week as possible. The new business model drives new requirements for our computers or servers, especially in the areas such as commercial organizations, social institutions and etc. The trend is very clear, we need rely on the stable computer systems all the time. The growth of demand makes high availability become very important. To a large extent, the business of many corporations and organizations rely on computer systems, any downtime will cause serious losses, key IT system failures may soon cause the breakdown of the entire commercial operation, so every minute of downtime maybe means the loss of revenue, production and profit, or even market position will be weakened.
Because of the incresement of key business, the requirements for continuous application protection become more and more intensive. With users' network and storage environment from an ordinary cable and direct-connect storage and upgrading to fiber or iSCSI SAN environment, the old dual-server hot backup solutions are far from satisfactory, so that users have to find new solutions. The solutions, which not only could compare with the original dual-server hot backup system but also have a great capacity for expansion, become the first choice of users. Cluster system could take advantage of the latest SAN and ISCSI links to form a number of nodes available to the core system, and it is convenient to add or delete nodes, which brings a strong expansibility. Therefore, the multi-node high availability cluster will become the potential choice for users of dual-server hot backup.
