Dual-machine Hot Standby is designed for server faults.
Server faults may be caused by various causes, such as equipment faults, operating system faults, and software system faults. Generally, it may take 10 minutes, several hours, or even a few days for technicians to restore the server to a normal state. From the actual experience, it usually takes more than a few hours to restart the server unless the server is simply restarted. If the technicians are not on site, the service will be restored for a longer time.
For some important systems, it is hard for users to endure such long service interruptions. Therefore, dual-host hot backup is required to avoid long service interruption and ensure the system's long-term and reliable services.
Determine whether to use dual-host hot backup. The correct method is to analyze the importance of the system and the degree of tolerance for service interruption, so as to determine whether to use dual-host hot backup. That is, how long can your users tolerate service restoration and how much impact will be caused if the service cannot be restored.
When considering dual-machine Hot Standby, you should note that in general, there will be a switching process for dual-machine Hot Standby, which may be about one minute. During the switchover, the Service may be interrupted for a short time. However, after the switchover is complete, the service will be restored normally. Therefore, dual-host Hot Standby is not seamless and uninterrupted, but it can ensure that normal services can be quickly restored in the case of system faults, so that the business will not be affected. If there is no dual-machine hot backup, once a Server failure occurs, the Service may be interrupted for several hours, and the impact on the service may be very serious.
The concept of server faults is much higher than that of switches and storage devices. The reason is that servers are much more complex than switches and storage devices. They are also complex systems that include both hardware, operating systems, and application software systems. Not only may Equipment Faults Cause service interruptions, but also software problems may cause the server to fail to work normally.
It should also be pointed out that some other protection measures, such as disk array RAID, and data backup are very important, but they cannot replace the role of Dual-machine hot backup. See related articles: Relationship between hot standby and data backup/Raid.
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