How do servers back up?
May 22,2021
Data loss and corruption is our business and website owners nightmare. Most of our data losses are caused by hardware failures, software errors, human error, and natural disasters. An effective way to protect your data from these disasters is to back it up. Proper server backup methods can minimize storage space, reduce the impact on computing resources and bandwidth usage, ensure data security, and restore data as quickly and easily as possible after a disaster. In this article, I introduce you to some server backup methods and help you choose the right one.

A full backup

A full backup is the simplest form of backup, containing all the folders and files that need to be backed up. We usually compress files to save space, but even a full backup can take up a lot of storage space. Heavy access to backup disks also requires additional bandwidth.

A full backup has the advantage of being easy to restore. Because complete data is readily available, data recovery is quick and easy. Ideally, you should always have full backups, because they are the most comprehensive and stand alone. However, doing so often takes time.

A full backup is usually performed weekly, except for major updates (such as an operating system upgrade or new software installation). Perform incremental or differential backups in intervals.

Incremental backup

Since full backups are time consuming, we may prefer incremental backups to reduce the time required to perform backups. An incremental backup only backs up data that has changed since the last backup. For example, assuming a full backup was taken on Monday, you can perform an incremental backup on Tuesday to back up files that have changed since Monday. On Wednesday, another incremental backup was performed on files whose backups had changed since Tuesday. Because the amount of data backed up per iteration is much smaller, storage space is saved and network bandwidth is reduced. It also allows you to keep multiple versions of the same file.

Incremental backups, however, use more computing power because each source file must be compared to the last full backup and each subsequent incremental backup to determine whether the data is new or changed. Also, the recovery process is slow. You first need to restore the latest full backup and each subsequent incremental backup. If one of the backups fails (full or incremental), the recovery will be incomplete.

3. Differential backup

A differential backup is between a full and incremental backup. Although incremental backups provide a middle ground by backing up all files that have changed since the last full backup or incremental backup. A differential backup is essentially a cumulative backup of all changes made since the last full backup. Restoring differential backups is faster than restoring incremental backups, and only the last full backup and the last differential backup are needed to create a full restore. To save storage space, set the differential backup to overwrite the last differential backup. As with incremental backups, differential backups require additional network bandwidth to compare the current file with the one that has been backed up in order to find and backup files that have only changed.

How to choose the right server backup method

4. Mirror backup

Mirror-based backups allow you to create a full disk backup of the entire system (or one or more partitions), including the operating system, applications, and all the data associated with them, not just files and folders. The backup is saved as a file called an image.

When you need to restore your entire system, mirror backup is the fastest recovery option. They are very effective in disaster recovery. You can choose to restore the entire server to exactly the same state as the new server, even if the server has different hardware. You can also restore individual files from mirror-based backups without having to restore the entire system. Backup images can be saved to a variety of different media, providing you with additional backup copies.

Which server backup method is right for you?

Be sure to consider which type of backup best suits your business needs. Ask yourself the following questions:

• What does your service level agreement say about the recovery time?

• What are the requirements for storing backups off-site? An incremental backup is a bad idea if the backup is sent in a remote location, since all backups must be retrieved before recovery can begin.

• What types of backups does your backup application support?

Here are a few options to consider:

• Monthly mirror backups, weekly full backups, and daily differential/incremental backups

• Quarterly mirror backups, monthly full backups and daily incremental backups