What is Data Redundancy? In computer systems, redundant data refers to the presence of other data besides the original data and allows correction of potential errors in either stored or transmitted information. This process is extremely important in networks as losing even one bit of data can result in the loss of entire networks. This concept was first introduced in IBM’s Personal Computer in 1981.
Redundancy can be defined as “the practice of making more than one copy of a source, or part, at the same time.” In the context of application security, we can take this up a notch and state it as “two independent copies of a network packet, each of which is stored in separate datachannel segments.” There are several layers of redundancy along the network fabric. The layer one, or layer two, is the lowest layer. The second datachannel, layer 2, is the first.
IT service providers should be familiar with data redundancy and normalization as they help to ensure system scalability. System failures are more likely when systems are scalable. Scalability is brought about by proper maintenance of the redundancy and normalization procedures. These procedures involve many factors such as availability of routing table, address matching procedures and database management systems. They also require application normalization and security procedures.
One of the most common forms of redundancy is creation of multiple locations for the same data in case of a failure in one of them. In the event of a server crash, you can create multiple copies of the server data in different locations. On the other hand, in the case of a network failure, you can maintain only one replicated site and then make all logical replicas from it. These procedures are known as multi-site redundancy or site normalization.
The other common form of redundancy is that done by reducing redundancy at the layer of the network which is much closer to the consumer end. This means that data is stored at different locations with lower latency or bandwidth, rather than being saved in the same server. This backup is called lower level of service, or LSN. It reduces data redundancy but also decreases the availability and reliability of the master data.
A business will typically have three types of redundant data storage: one at its physical site, one in cloud storage, and one at the consumer end. Each of these redundant storage areas will be different in terms of their level of redundancy. We need to understand how this system works by breaking it down into three main categories: physical, logic, and replicated data.
The physical duplication of information happens when there is only one copy of a table or a group of tables at the physical site. For example, if there are ten users who log in to the database at the same time, then the logical redundancy occurs first. The two users who did not log in to the system will be the ones who are logged on first. The third user, who has already logged in, will be last and will be the last person who will have access to the data on that particular table or group of tables.
The logical duplication of data happens when two or more users can share the same table or group of tables. Logical duplication occurs when more than one user can access the same data fields, or data pieces. In case you have duplicate data fields or data pieces, then you might as well have redundant copies. However, this kind of redundant data storage does not happen in case of an application context alone.