1. Field of the Invention
This invention relates to data transfer between data storage and more particularly to the automatic backup of related data stored in consistency groups across multiple storage cells based upon predetermined triggering events.
2. Description of the Related Art
Information technology is the lifeblood of most businesses in today's world. Data is often a business' most valuable commodity. Data must be protected while being accessible to employees, customers, and/or trading partners across different time zones. In order to prevent data loss due to component or system failure or because of an unforeseen natural disaster, many companies rely on data backup systems. These systems range from small, less expensive devices such as removable tape drives or optical disks, to large storage servers, such as the Enterprise Storage Server (ESS) by IBM®.
Computer systems regularly and sequentially back up data to local or remote storage subsystems. Remote electronic copying of data storage volumes is a frequently used strategy for maintaining continuously available information systems in the presence of potential data loss. Storage systems use different data storage or copy techniques to back up data. Most backup techniques, however, try to achieve two important objectives. First, data storage systems try to maintain an accurate replica of the data. Second, data storage systems try to maintain a consistent replica of the data. Maintaining accuracy requires that as data is copied from one storage medium to another, no errors are introduced. Maintaining consistency requires that as data is copied from one storage medium to another, no data is lost or omitted. Accuracy may be ensured in the case of data corruption or media failure by copying a consistent replica of the data from a backup source.
Ironically, one problem with most backup copy methods and apparatuses lies in their regularity. For example, the system administrator in charge of a business' data may schedule a data backup every night at midnight, when the data is least likely to be used and resources needed to accomplish the backup are least likely to interfere with ongoing business operations. The problem with this approach is that the administrator may have no way of knowing when critical changes to the data occur that need backing up. With round-the-clock access to business data or applications, critical data may be written to memory at 1:00 a.m., right after a data backup. This data is now vulnerable to loss for twenty-three more hours until the next backup occurs.
Some businesses solve this problem by limiting access to data to certain times of the day or to certain people. This approach is unsatisfactory to most businesses that need constant access to data by many people. Another solution is to increase the frequency of the backups. This approach is also problematic because backups require computer resources and time. More frequent data backups increase computer costs and reduce human efficiency. This approach also forces companies to make the unenviable choice between the cost of losing data and cost of backing it up.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that do not require an administrator to determine when to backup data. It would be an advancement in the art to provide such an apparatus, system, and method where critical data could be backed up whenever it changes, independent of any backup schedule. It would be a further advancement to provide such an apparatus, system, and method that could automatically backup groups of related data whenever one of the related data changes. Such an apparatus, system, and method are disclosed and claimed herein.