The term backup and restore refers to the technologies for making backup copies of the data and applications to the secondary device and use those copies to recover the applications and the data when disaster strikes.
Strategy & Planning
The technologies and the practices of backup your data and application depend on how critical the data is and how much it is worth for the organization. The first step in creating a backup strategy is to determine the Recovery Time Objective (RTO) and Recovery Point Objective (RPO).
To know more about RPO and RTP, please read my blog on RPO & RTO Understanding the difference.
Backup Devices and Services
Generally speaking, we have four options to decide on what type of device or service we will back-up our data.
Tape Drive – The oldest medium, offers low-cost, high capacity data storage, LOW read/write performance which makes tape a poor choice for incremental backup or any other back-up practice that updates back-up whenever there is a change in the data.
Hard Disk Drives (HDDs) or Solid Disk Drives (SSDs) – Today for backing up the data we use HDD and SDD in the form of a standalone external drive or as a part of a backup server. Both give fast high performance and good options for continually updates the backup with short RPO and RTO.
Backup Server – A server dedicated to backup files stored on multiple clients. The server has huge storage and specialized software for scheduling and managing backups. The disks used in the backup server are configured for redundancy to protect backup data and ensure backups continue in the event of disk failure.
Cloud Backup – The practice of taking backup of files and applications are most flexible of all. We can use the cloud to back up our files, application data, entire physical or virtual servers. The cloud servers are virtual hence, we can schedule backups frequently as we like, scale easily and cost-effectively. The best in cloud backup is that there is no need to move back up media physically to other locations for protection against disasters.
Common Methods & Solutions
In this section, we will know about the most commonly used backup and restore methods. The methods we will choose depends on the following:
- RPT & RTO.
- Scalability.
- Geographic Distance.
- We are protecting personal, SMB, or Enterprise Business data.
- We are backing up only data, data & applications both, entire physical or virtual machine.
Full-Image Backup Only – Full image backup happens periodically of a complete data source we want to protect. To restore, we replace the most recent backup image file. The full image backup is fast but this method is not recommended where we need short RPOs and ETOs because they are time-consuming and like others, it cannot be performed frequently.
Incremental Backup – Once the full image backup is performed then performs the periodic backups of the data that changed since the most recent or the last backup activity. Incremental backup speeds up the restore time.
Differential Backup – In the differential backup, the backup happens for all the data that has changed since the last full image backup. In this backup activity, the backup time increases but restoring requires only two files to be restored i.e. the latest full image backup and the latest differential backup.
Continuous Data Protection (CDP) – CDP or real-time backup, save the copy of every change we made to the data and store it on a separate storage device and keep track of all the changes. Since CDP restore the data from the most recent change made to the data, it provides the most comprehensive protection to our data.