All the time, users do not pay enough attention to data integrity and availability. They mistakenly think data security can be ensured after data backup. However, data backup does not equal to data disaster tolerance, and the backup may be lost or damaged due to different kinds of factors like earthquake and fire disaster. For enterprises, they should enhance the ability to data disaster tolerance so as to further deal with potential unsafe factors. Some users may ask what disaster tolerance is. Simply speaking, data disaster tolerance is to reduce or avoid data losses caused by disasters to the largest extent. Backup and recovery are 2 most important parts, which offer data disaster recovery and data management. Moreover, data availability should be enhanced, and measures should be powerful enough to prevent important data from being influenced or damaged by natural disasters. Talking about disaster tolerance, users first think of data backup. Well then, what is the relationship between data backup and disaster tolerance? For enterprise, the loss of key data will influence business development to a large extent or even result in serious economic losses. Nevertheless, many enterprises still haven’t known the real meaning of disaster tolerance and mistakenly think building backup system can keep data absolutely safe. Actually, disaster tolerance system is also indispensable apart from backup system, and the relationship between backup and disaster tolerance can fully show us the importance of disaster tolerance. Backup is the foundation of disaster tolerance We can say data backup is the last line of defense, which aims at recovering data quickly after system crash. Though this is one of disaster tolerance types, it has big limitations. Currently, traditional backup still adopts cold backup, and backup system is managed in machine room. Once the machine room suffers a disaster, data on backup tape will be destroyed. Disaster is not simple data backup We have said data backup is the most fundamental type of disaster tolerance, but backup is far from being enough. Real data disaster tolerance can make up the defects of traditional backup and recovers system timely when disasters emerge. Therefore, disaster tolerance is a computer information system which can prevent different kinds of disasters for IT. Therefore, paying enough attention to data disaster tolerance can help further ensure data security, and users can make use of core data to cope with market competitions.