The realization of Sybase dual-machine hot backup

In today's business activities, Sybase is the mainstream server platform for data hosting, and the availability of information systems based on the database system has become one of the most important metrics for measuring its resource utilization:

Strong performance: The operation can be run on different servers, the performance of the whole system will be greatly improved;

High availability: A host outage in a clustered system does not affect the user;

Save investment: High system stability leads to avoidance of business losses caused by system crashes, especially for data loss.

At the same time, the development of computer technology, PC Server processing capacity is more powerful, while its performance/price is more and more high, coupled with the traditional minicomputer due to maintenance and upgrade difficulties, high cost, is being challenged by PC server. Therefore, the PC server's cost-effective system is increasingly favored by users. Because of the security factors of PC server, stable and reliable and continuous operation of the system becomes the key of the system, so the setup of Sybase dual-machine hot standby system is more and more popular.

In general, when the system is not running normally, we need to use manual method to identify, analyze, recover and test the fault. These all take a long time. During this time, the system must pause to wait for recovery, resulting in incalculable economic losses for the business.

Fault tolerance is an important guarantee for the stable, reliable, effective and continuous operation of computer application system, it solves the reliability problem of computer application system by means of redundancy, and has the advantages of simple installation and maintenance, stable and reliable monitoring and so on. When a host fails, the software can start another host in time to replace the original host task, to ensure the reliability of user data and the continuous operation of the system.

Two-machine fault-tolerant basic architecture

Dual-machine fault tolerance is to ensure that the data will never be lost and the system never stop, the general use of Intelligent disk array cabinets to ensure that the data never lost, the use of dual-machine fault-tolerant software to ensure that the system will never stop. Its basic architecture can be divided into two modes:

Dual-machine Mutual assistance (Dual Active) mode

Dual-Machine Hot Standby mode.

Dual-machine Mutual assistance (Dual Active) mode

The so-called dual-machine hot standby is two Sybase hosts are all working machines, under normal circumstances, both machines provide support for information systems, and each other to monitor the operation of each other. When a host is abnormal, can not support the normal operation of information systems, another host is the active takeover (Take over) Abnormal machine work, continue to host information operations, so as to ensure that information systems can operate uninterrupted, and achieve the function of Non-stop (non-stop), But the load on the normal running host (Loading) will increase. At this point, the abnormal machine must be repaired as soon as possible to shorten the work handover recall of the normal machine.