Difference Between Backup and Replication<\/h2>\n
What are the main differences between backup and replication? We\u2019d like to draw your attention to some distinctions. But first, let\u2019s get clear about the definitions:<\/p>\n
What Is Replication?<\/h3>\n
As we mentioned, replication is concerned with making copies of data. Exactly what data is being replicated will depend upon what users wish to protect. Replication might cover:<\/p>\n
- \n
- Copying, in real time, the files and folders on a computer<\/li>\n
- Mirroring an entire operating system at the OS or disk level<\/li>\n
- Copying only aspects of the OS, such as applications and settings<\/li>\n<\/ul>\n
Replication can be used to instantaneously and automatically mirror system resources to a secondary location \u2014 or several of them.<\/p>\n
For instance:<\/p>\n
- \n
- A replication program could instantaneously replicate changes to a mission-critical database, such as a CRM MySQL table, to a second onsite copy for quick failover, and to an offsite copy for disaster recovery<\/a> (DR) in the event that all onsite resources are inaccessible.<\/li>\n
- Replication could be used to replicate all on-premises servers to backup servers in the cloud. Failover to cloud resources could automatically occur if onsite resources were unavailable, such as during a power outage (if the company did not have backup power).<\/li>\n
- Replicate copies are taken so that there is a secondary system which can mirror the primary system to ensure seamless failover and to minimize the recovery time objective<\/a> (RTO) \u2014 the maximum length of time it will take to restore operations.<\/li>\n<\/ul>\n
For replication systems, the RTO, for failover, would typically be measured in minutes. Unlike some backup use cases (for instance, hardware storage failures), these interruptions to routine operations are also expected to be temporary in nature and the business hopes that operations can quickly be resumed on the primary system.<\/p>\n
All these data protection strategies are important in order to ensure business continuity<\/a> by ensuring the provision of applications and systems in the event of disaster and to make them available in real time. But, as we will soon explain, none of these approaches are considered backup.<\/p>\n
What Is Backup?<\/h3>\n
Backup creates a point-in-time copy of a file system or another digital asset (such as a database). Unlike snapshots \u2014 another \u201cbackup-like\u201d technology \u2014 backup contains the files themselves, rather than a note of changes since the last run.<\/p>\n
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<\/a><\/span><\/span><\/div>\nA backup can be used for many disaster recovery (DR) use cases. Most basically, if a change degrades stability or otherwise compromises data, restoring from a backup can bring a system back to its previous state. Some backup approaches (like disk imaging) can even be used to back up a system onto new hardware in the event of mechanical or physical destruction.<\/p>\n
Finally, backup can be used for compliance and archival purposes by businesses that need to take a picture of their system at a point in time for regulatory reasons.<\/p>\n
Further reading<\/span> Frequently Asked Questions About Backups: Everything You Should Know<\/a><\/p>\n
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<\/div>\n<\/div>\nHow Do They Work?<\/h2>\n
Backup<\/h3>\n
Backup approaches typically involve either making full copies of an origin device onto a target medium (full backups) or writing notes of additions, changes, and deletions (incremental or differential backups).<\/p>\n
These approaches are used to ensure either that a system can be restored to a specific point in time with one operation (restoring from a full backup), or that the same thing can be achieved through aggregating a series of files which note changes to the file system.<\/p>\n
Further reading<\/span> Backup Types Comparison<\/a><\/p>\n
Replication<\/h3>\n
Here is another difference between backup and replication: replication doesn\u2019t involve taking historical copies \u2014 instead it simply replicates every change live and in real time. With replication, the moment the primary file system is changed, those changes are reflected onto the target medium.<\/p>\n
The writing process can happen instantaneously (synchronous replication) or can entail some latency (asynchronous or near synchronous replication). The latter approach involves the replicate storage acknowledging its writing operations back to the primary storage and is popular on storage devices such as network attached storage<\/a> (NAS) devices.<\/p>\n
Use Cases<\/h2>\n
Backup<\/h3>\n
Backups are used to make sure that there is a backup point for everything from user endpoints, like desktops, through to servers. If there is a machine which businesses need to ensure can be restored in the event of degradation, accidental deletion, or other error, then backups are the tool of choice.<\/p>\n
Further reading<\/span> Desktop Backup<\/a> with MSP360<\/p>\n
Further reading<\/span> Server Backup<\/a> with MSP360<\/p>\n
Replication<\/h3>\n
Replication is used to protect mission-critical applications such as CRM servers, payment processing machines, and anything else which the business needs to have operational all of the time. If even five minutes of downtime is too much, then a replica will be provisioned for failover.<\/p>\n
Which Costs More?<\/h2>\n
Backup<\/h3>\n
Backup is usually the cheaper of the two approaches. That\u2019s because, in order to take a backup, users typically just need to provision some storage and a backup program to run the operations.<\/p>\n
Further reading<\/span> Benefits of Cloud Storage Explained<\/a><\/p>\n
Replication<\/h3>\n
To set up a replication system, by contrast, users would need to provision parallel resources.<\/p>\n
In order to provide replication for a storage center, for instance, users would need to set up computer storage with the same capacity as the primary storage system at a remote site. This could entail substantial hardware costs.<\/p>\n
Which Needs More Resources?<\/h2>\n
As a general principle, replication approaches also need more resources.<\/p>\n
While a backup administrator, software, and some storage media might be enough to ensure a backup strategy within a small business, in order to set up proper replication of a mission-critical system, businesses might need to assign significant resources to the rollout. They might also need to implement new business processes, teach staff how to manage failover, and invest in new infrastructure to support the continued operation of replication systems.<\/p>\n
Benefits Head to Head<\/h2>\n
Backup approaches:<\/p>\n
- \n
- Are simple to implement: Users simply need to determine which backup approach is appropriate to support their target RTO and recovery point objective (RPO).<\/li>\n
- Provide high isolation: Many backup systems \u2014 such as tape libraries \u2014 are stored cold. Additionally, they\u2019re not typically connected live to primary systems. Thus, if the primary system is attacked by a virus or ransomware, the backup copy will remain clean.<\/li>\n<\/ul>\n
Further reading<\/span> Backup Best Practices In Ransomware Protection Strategy<\/a><\/p>\n
- \n
- Are inexpensive: Comparatively speaking, backup approaches don\u2019t cost a lot to set up and maintain.<\/li>\n<\/ul>\n
Replication approaches:<\/p>\n
- \n
- Focus on disaster recovery: If quick RTO is what\u2019s required, then replication approaches have the advantage over backups.<\/li>\n
- Provide high availability: Likewise, for resources that need to be highly available \u2014 such as components of a cloud \u2014 then ensuring replication makes more sense than backup. Of course, in many instances both should be used!<\/li>\n
- Facilitate quick RTO: RTO for backup is typically longer than for replication systems.<\/li>\n<\/ul>\n
Shortcomings Comparison<\/h2>\n
Each approach has its disadvantages, too.<\/p>\n
Backup<\/h3>\n
For backup approaches, there can be a relatively long time between backup snapshots. The length of time between two backups is termed the recovery point objective<\/a> (RPO). The longer the RPO, the more data a company stands to lose in the event that recovery from that backup is required.<\/p>\n
Additionally, the RTO is typically longer. This is because an entire operating system \u2014 potentially across a whole network of servers \u2014 needs to be written. The RTO for replication is often almost non-existent, because these are typically parallel systems that are continuously running and being updated.<\/p>\n
Replication<\/h3>\n
Replication\u2019s main disadvantage is that it is more expensive to maintain than backups. Backups can use highly cost-effective LTO storage by storing petabytes of data at low cost. For replication, because the systems are expected to be ready for near-instant failover, this storage class is sometimes not viable.<\/p>\n
- Are inexpensive: Comparatively speaking, backup approaches don\u2019t cost a lot to set up and maintain.<\/li>\n<\/ul>\n
- A replication program could instantaneously replicate changes to a mission-critical database, such as a CRM MySQL table, to a second onsite copy for quick failover, and to an offsite copy for disaster recovery<\/a> (DR) in the event that all onsite resources are inaccessible.<\/li>\n