Backup over WAN / Internet

Traditionally, backup in commercial offices has been on backup media such as magnetic disks, CD-ROMs, DVDs, etc. When the office administrator decided to backup the data, he had to close all open applications and take the backup of all files in the office server. If there were branches of a company spread over a large area, then in each branch there would be a person who would religiously take the backups.
 
But what happens when the changes made in one branch are needed in another branch? Chances are that the branch would get the latest data only when released by the main office. Nowadays, it is very likely that the BPO operations of a company headquartered in New York take place in several other locations such as Bangalore and Shanghai which are thousands of miles away. Transferring data may take a long time in such a scenario.
 
Yet, the need to backup data and the availability of that data to all users is critical to the smooth running of the enterprise. This is possible by using backup over WAN (Wide Area Network) or Internet. This type of backup works in one of two ways:


Both these methods of data backup are effective, but each has slightly different requirements and implications. The first type of WAN backup is possible and implemented in an organization where there are a large number of users who connect to the company data system once a day or so. When they connect to the backup server, the files are synchronized and new data is available to the remote user. However, this means that a lot of information has to be stored on the network server. When these are made through the Internet, it is termed as ‘Backup over Internet’.
 
The other method is the distributed file system information. In this type of backup, only the bytes which have changed are backed up. This allows for a smaller memory foot print in the backup server since only the changes made are backed up.
 
The backup strategy used by your organization depends on its data usage pattern. If there are a large number of mobile users who do not make very large changes to the data, a centralized backup server is a good choice. If you have a number of fixed offices with their local servers, using a distributed server to store data is most appropriate. In any case, backup over WAN or Internet is better than using magnetic tapes and other removable media since it allows you to backup your distributed data in a single location and retrieve it from any other location.