Data loss and data corruption are nightmare for most individuals and businesses. You may lose data due to hardware failures, software bugs, human action or natural disasters. Backups are an effective way to protect your data from those disasters. By using the right server backup methods, you can keep your data safe in a way that minimizes storage space and reduces the impact on computing resources and bandwidth usage. In case disaster happens, data recovery process should be as quickly and easy as possible. In this article, let us introduce a few backup methods for your servers and help you choose the right methods.
A full backup is the simplest form of backup, which contains all of the folders and files that you selected to be backed up. Files are usually compressed to save space, however, even when compressed full backups may consume a lot of storage. Additional bandwidth is also required by the heavy access to the backup disk.
The advantage of full backups is the ease of restoration. As complete data is readily available, data recovery is fast and easy. It would be ideal to make full backups all the time, because they are the most comprehensive and are self-contained. However, it is often too time costuming to do so.
With the exceptions of major updates such as OS upgrades or new software installations, full backups are typically performed on a weekly basis. Either incremental or differential backups are performed in the intervals.
Because full backups are so time consuming, incremental backups were introduced as a way of decreasing the amount of time that it takes to do a backup. Incremental backups only backup the data that has changed since the previous backup. For example, suppose a full backup was made on Monday, then an incremental backup may be performed on Tuesday to back up files that have changed since Monday. On Wednesday, another incremental backup is performed to backup files that have changed since Tuesday. As the volume of data backed up at each iteration is much smaller, it saves storage space and uses less network bandwidth. It also allows retention of several versions of same files.
However, incremental backups use more computing power, because each source file must be compared with the last full backup and each subsequent incremental backup in order to determine whether data is new or changed. Moreover, recovery process is slower. You will first need to restore your most recent full backup as well as every subsequent incremental backup. If one of the backups fails (either the full or incremental), then recovery will be incomplete.
Differential backups fall somewhere in between Full and Incremental backups. Whereas incremental backs up all the files modified since the last full backup or incremental backup, differential backup offers a middle ground by backing up all the files that have changed since the last full backup. A Differential backup is essentially a cumulative backup of all changes made since the last full backup. Restoring a differential backup is a faster process than restoring an incremental backup because only the last full backup and the last differential backup is needed to create a complete restoration. To save storage space, you may set your differential backups to overwrite your last differential backup. Like incremental backups, differential backups also require additional network bandwidth to compare current files to those that are already backed up in order to find and backup just changed files.
An image-based backup allows you to create a full disk backup of your entire system (or one or more partitions), including your operating system, your applications and all of your data associated with it, rather than just files and folders. The backup is saved as a single file that is called an image.
Image backups are the fastest recovery option when you need to restore your entire system. They are very effective in disaster recovery. You can choose to restore your entire server exactly as it was to a new server, even if that server has dissimilar hardware. You may also restore a single file from the image-based backups without having to restore the entire system. Backup images can be saved to a variety of different media, giving you additional copy of backup.
Which Server Backup Methods are Right for You?
It is important to consider which backup type is best suited to your business needs. Ask yourself the following questions:
- What does your service-level agreement dictate in regard to recovery time?
- What are the policies regarding storing backup tapes offsite? If backups are shipped offsite, incremental backups are a bad idea because you have to get all the tapes back before you can begin a restoration.
- What types of backups does your backup application support?
Here are a few options for you to consider:
- Monthly image backup, weekly full backup, and daily differential / incremental backups
- Quarterly image backups, monthly full backups, and daily incremental backups
It is always a good idea to set your backups to automatically run on schedule. Remember to create an image backup before making any type of system changes like updating your OS, adding new hardware, updating drivers, etc. Keep in mind that using any method of backup is better than having no backups at all.