Continuous Data Protection and Scheduled Backups are methods of transmitting enterprise data into data repositories for online or offline storage. Continuous Data Protection (CDP) is a process in which data is sent into storage even as it is being generated, modified, or changed. Scheduled Backup, as the name indicates, is a backup method whereby data is sent into storage at predefined timeframes known as the “backup windows”.
CDP systems are recommended for organizations in which data changes frequently; the amount of data is large and the business cannot afford downtime of any kind without incurring heavy losses. Businesses, which work round the clock and must access data at all times, may also, find that allotting backup windows for scheduling backups impossible. Continuous data backup may suit them better.
The installation of CDP hardware is also very simple. The programming is straightforward. Backup software and online backup vendors provide user-friendly interfaces that can help the end user set up the CDP process painlessly and effortlessly. Once the program has been set up, backup becomes an automated process that requires little or no human interference.
CDP is always automatic. It creates continuous storage snapshots and preserves records of every transaction. There are several predefined Recovery Point Objectives (RPOs) and Recovery Time Objectives (RTOs) that get automatically defined even as data is being sent into storage. This makes it wholly possible to recover records on the basis of a time stamp or with reference to a point in time. In fact, a CDP recovery is much faster than a recovery from a disk or a tape backup as it is instantaneous. For instance, if the system suddenly becomes infected by a virus or a Trojan, the IT administrator can identify a point in time at which the system was clean and recover data up to that point instantly. Thus, loss of data can be minimized and the system can recover quickly without loss of business.
Scheduled backups occupy a niche at the other end of the backup spectrum. Scheduled backups may require identification of backup windows or timeframes when the IT hardware/software resources of the enterprise are not engaged in business transactions or are relatively idle. Organizations, whose data changes slowly, are not voluminous and downtime is not a business problem, can afford to consider scheduled backups in place of continuous data backup. Such organizations may have large backup windows.
The set up of a scheduled backup may be automatic or manual. IT administrators may use the graphical user interfaces provided by backup software vendors or online backup service providers to automatically set up a schedule for the backup of mission critical files. The scheduled backup will run at the specified time and backup all the files in the backup set that has been defined by the IT administrator until another file is added to the backup set or the time is rescheduled. Manual backup schedules can be initiated whenever the IT administrator thinks necessary and in accordance with contingencies that may arise demanding backup of specific files and folders.
The implication is–scheduled backups do not backup all files as they change. They backup changed or unchanged files at specified times as they find them at that point in time. RPOs and RTOs can only be defined with reference to the time of backup or schedule of backup and the backup set. Files and folders can be recovered only up to the point where a clean backup occurred—which may be the previous day, previous week or previous month when the last backup was scheduled to run and ran successfully. Data loss can be huge in such circumstances.
Many organizations may like to mix and match backup modes. IT budgeting constraints may requires enterprises to set up continuous backup processes for mission critical data; schedule time bound backup windows for less important information of the enterprise and near continuous data backup schedules for data that is important but not very mission critical.