What is backup and restore?

Backup and restore is used if the original data and applications are lost or damaged due to a power outage, cyberattack, human error, disaster or some other unplanned event.

With digital transformation in full swing, the demand for increasingly scalable, capable and affordable backup and recovery solutions is greater than ever. Backup and restore is an essential component of any business’ disaster recovery strategy.

How you back up your data and applications—meaning how often and where you store them—depends on the cost of losing access for any length of time. It also depends on the cost of replacing or re‑creating the data when it is permanently lost.

Typically, the first step in creating a backup strategy—especially an enterprise backup strategy—is to determine recovery time objectives and recovery point objectives for each data source and application.

• Recovery time objective (RTO) is the maximum time that a business can be without access to its data or applications. It defines how quickly those resources must be recovered to resume operations.

• Recovery point objective (RPO), refers to the amount of data you can afford to lose and effectively dictates how frequently you need to back up your data to avoid losing more.

RTOs and RPOs vary depending on the business that you’re in and the individual applications and data in question. Mission‑critical applications—for example, the e-commerce system for a major online retailer or the trading application at a brokerage—might require microscopic RTOs and RPOs. In each case, downtime might cost millions per minute.

But the brokerage’s email system might require shorter RTOs and RPOs than the retailer’s email system because the brokerage might require a comprehensive email audit trail for regulatory compliance. 

Beyond RTO and RPO, other factors that determine your choice of backup and restore technology include your need for scalability, data security and physical distance. For example, you might need to maintain your backups far enough away from your production infrastructure to ensure recovery from a local power outage or disaster.

What type of device or service will you use to back up your data? Generally speaking, you have four choices.

Tape is the oldest backup medium in use today. It offers low‑cost, high‑capacity data storage. However, its slow read/write performance makes tape unsuitable for incremental backup, continuous data protection (CDP) or other methods that update backups whenever data changes.

Tape is also more prone to physical wear and damage than other storage media. Therefore, it needs to be closely managed and constantly tested to ensure that it works when it’s time for recovery. 

For these reasons, tape is a better choice for nightly or weekly backups or for cost‑effectively archiving data that your organization wants or needs to keep. However, this data is not required to quickly bring the business back online when an outage or disaster occurs.

Most data today is backed up to a hard disk drive (HDD) or solid-state drive (SDD), whether that drive is a stand-alone external drive or part of a backup server. Both offer faster read/write performance than tape, making them a good choice for continually updated backups and short-RTO/RPO backup scenarios.

SSDs are increasingly popular because they offer faster read/write times than HDDs. They also require less physical space to store the same amount of data and consume less power, even though they are more expensive per gigabyte. If HDDs and SDDs have a drawback, it’s that they aren’t scalable—if you need more backup capacity, you must purchase and install a new physical disk.

A backup server is a dedicated server built specifically for backing up files stored on multiple client computers on the same network. The server is outfitted with significant disk storage and specialized software for scheduling and managing backups.

Backup server disks are often configured for redundancy to protect backup data and ensure that backups continue during a disk failure. An onsite backup server can be a cost-effective backup solution for a small office but does not protect backup data against local outages or physical disasters.

Cloud backup backs up your data and applications through a corporate network or internet connection. The data is stored on a physical or more likely, virtual backup server at a remote data center operated by your company, a hosting provider or a cloud services provider.

Cloud backup is typically the most flexible type of backup. You can use it to back up files, application data, or entire physical or virtual servers. You can schedule backups as frequently or infrequently as you like. Because cloud backup servers are typically virtualized, you can scale easily and cost-effectively as needed.

Cloud backup eliminates the need to physically move backup media to another location (and the larger RTOs and RPOs that can result) for protection against local power outages or disasters.

What follows is a list of the most commonly used backup and restore methods. The method or mix of methods you choose will depend on the factors mentioned earlier (RTO, RPO, scalability, security, geographic distance requirements) as well as the following factors:

• Whether you’re protecting personal, small business or enterprise data
  
  
• Whether you’re backing up just data, data and applications or entire physical computers or virtual machines
  
  
• Whether you’re relying on the backup methods your service provider offers

• Whether your budget supports the solution

Full-image only backup periodically backs up a complete copy of the data source you want to protect. To restore lost data, you simply replace it with the most-recent full-image backup. Full-image restores are fast, but because full-image backups can be time-consuming and can’t be performed as frequently as other backups, this method isn’t well suited to shorter RTOs or RPOs.

Incremental backup starts with a full-image backup and then performs periodic backups of only the data that changed since the most-recent backup. Typically, after a set number of incremental backups, another full-image backup is performed and the cycle starts again.

To restore data, you first apply the most-recent full-image backup and then apply each subsequent incremental backup to the target RPO. Incremental backup saves time by allowing fewer full backups and speeds restore times for recently changed files.

Differential backup backs up all data that has changed since the last full-image backup. To restore data, you first apply the most-recent full-image backup and then the most-recent differential backup. Backup time increases with each successive differential backup, but restoring requires applying just two backup files—the latest full-image backup and the differential backup).

Continuous data protection (CDP), sometimes called continuous or real‑time backup, saves a copy of every change immediately. Each copy is stored on a separate device and carefully tracked. CDP eliminates the interruption of discrete backups because backup happens constantly. As CDP can restore data from the most recent change or from any specific point in time, it provides the most comprehensive and granular protection for your data.

Bare‑metal backup captures an entire computer or server, including applications, data and the operating system. This enables restoration to bare metal hardware, which has no preinstalled operating system or software.

A backup and restore method for virtual machines (VMs), instant recovery maintains a continually updated backup VM for the production VM. When it’s time to restore, the system redirects the workload to the backup VM in real time, allowing users to continue working without interruption while IT staff restores the original VM.

Instant recovery offers the advantages of zero RTO and RPO but often, the performance of the backup VM is slower than the original VM.

Windows 10 Backup and Restore makes periodic full-image backups of your files on a schedule that you specify. It can also create a backup image of your entire system—OS, applications, files, settings and more—so that you can recover everything if needed. An additional tool called File History can be set to automatically save multiple versions of a file so you can recover the file to a specific version or point in time.

Built into the Apple MacOS, Time Machine automatically performs hourly, daily and weekly backups of your entire Mac system. It can save the backup to your Mac, an external drive or to an AirPort Time Capsule (if you have one—Apple no longer makes them).

When restoring files, Time Machine allows you to browse dated backups and select your recovery point. You can also back up files on your Mac—such as documents, photos and songs—to iCloud.

You can back up and restore MySQL, PostgreSQL and SQL databases easily from the command line or with third-party tools available separately.

You can back up your iPhone with iTunes on your computer or with iCloud in the cloud. Depending on the amount of data you’ve stored on your phone, you might need to purchase more iCloud storage.

Android Backup and Reset is a backup tool built into all Android mobile devices that backs up your data and settings to Google Drive. In addition, certain Android phone vendors, such as Samsung, offer their own backup and restore apps and data storage services.