A common misunderstanding in web hosting is to assume that backup, snapshot and disaster recovery mean the same thing. In reality, these terms are not interchangeable, as each one protects against different problems. Indeed, knowing the difference can be crucial when a website, application or other workload needs to be restored. In this post, we explain the differences between backup vs snapshot vs disaster recovery and discuss the key considerations when deciding the level of protection and recovery planning a workload requires.
Contents
What is a backup?
A backup is a copy of data taken at a specific point in time. Depending on how a backup service is configured, the data could include individual files, applications, websites, databases, or even an entire server. Its purpose is to restore that data if the original is deleted, corrupted or becomes unavailable.
A good server backup strategy goes beyond simply making a copy. Businesses should also consider the frequency at which backups are taken and how long to retain them. For instance, if data changes throughout the day, daily backups might be insufficient, while a short retention period may prevent restoring data from an earlier point in time.
Another consideration is where to store backups. Ideally, they should be stored separately from the live server to avoid being affected by issues with that environment. They should also be tested to ensure they will work if they are needed for recovery.
For more information, read: A Practical Guide to Backing Up Websites and Data
What is a snapshot?
Unlike a backup, which creates a duplicate, a snapshot only records a server’s state at a particular point in time. Its main use is for when a business needs to roll a system back after a failed update, configuration change or other problem.
As the system keeps a record of any changes since the snapshot was taken, the system can be returned to the earlier version if needed. This is different from a backup, where data is restored from a separate copy.
Snapshots can use the same storage as the live system, making them more suitable for short-term rollback than long-term data protection.
What is disaster recovery?
While backups and snapshots help with recovery, the term ‘disaster recovery’ refers to the actual process of restoring IT services after a major incident.
This requires a disaster recovery plan that covers the infrastructure and systems needed to resume services, the data to be restored, the people responsible for recovery and the procedures they need to follow. If the usual environment is unavailable, e.g. due to a data centre fire, alternative infrastructure or locations may also be required.
In this respect, disaster recovery is a key element of business continuity planning. Rather than simply enabling lost data to be restored or a system to be rolled back, its purpose is to get critical services up and running again.
Backup vs snapshot vs disaster recovery
The following chart highlights the differences between backups, snapshots and disaster recovery:
As each approach is different, it is important that businesses understand the different kinds of protection each one provides.
Why RAID is not a backup
RAID (Redundant Array of Independent Disks) is when several physical drives are combined to form a single storage system. Depending upon configuration, RAID can improve performance and provide resilience against individual drive failure; however, it is not a backup.
Crucially, RAID does not give protection against incidents that affect the entire server or location. Moreover, if data is accidentally deleted, corrupted or compromised, these issues can affect the data stored across the RAID system. So, while RAID provides storage resilience, businesses will still need backups to recover data if the original becomes lost or damaged.
How to decide what your business needs
Understanding the right level of protection your business needs depends on how important a workload is and the impact of data loss or service unavailability. An in-house information site for employees, for instance, may have different recovery requirements from an ecommerce store that takes orders across the day.
Two important measures to consider are the Recovery Point Objective (RPO) and the Recovery Time Objective (RTO). RPO takes into account how far back in time a business needs to recover its data, while RTO asks how long a service can acceptably remain offline.
Businesses therefore need to know how much data they can afford to lose, how quickly they need the service to resume and who is responsible for recovery. The proposed recovery process should also be tested to ensure it works.
Read more: Futureproofing Your Data with Backup Strategies
Questions to ask your hosting provider
Before looking for backup or recovery solutions, businesses should first ask whether some features are included in their hosting plan.
- Are backups included?
Check whether these form part of the hosting service or if a backup solution needs to be purchased separately. - What are the frequency and retention periods?
Find out how often copies are taken, how long they are kept and if you can change these settings to suit the business’s needs. - Where are backups stored?
Ask whether the copies are kept separate from the live infrastructure. - How does restoration work?
Check what can be restored (e.g. files, apps, databases, entire servers, etc.) and whether it’s the business or provider that starts the process. - Are snapshots separate from backups?
Also ask what disaster recovery options are available for more critical workloads.
Conclusion
Making critical workloads more resilient requires layered protection. Backups enable data to be recovered, snapshots allow systems to roll back to an earlier state, and disaster recovery lays out the process of restoring services following a major incident. Understanding how these differ and the role they play helps businesses put the measures in place that are right for their needs.
Speak to our team to discuss your backup and recovery needs or visit our Remote Backups or Advanced Backup and Disaster Recovery pages.
