Difference Between Backup and Replication

The general perception of cloud backup is that, you make copies of your data on the cloud whereas, cloud replication is the creation of copies as well; including an initial replica of the entire system. This constitutes a confusion situation, where one is difficult to differentiate from the other. In order to question which one is necessary, it is essential to develop an understanding of the two.

Cloud Backup & Replication: Differentiating the two

The general perception about cloud backup and cloud replication isn’t entirely incorrect. Backup involves making a copy or copies of  data. Whereas Replication is the act of copying and then moving data between a company’s sites. It is typically measured in Recovery Time Objective (RTO) and Recovery Point Objective (RPO). Replication is of two types: synchronous and asynchronous.

Synchronous Replication

 In synchronous replication, your data is replicated in real time. After the entire system is replicated, the changes made are synced. This ensures that if your system crashes due to a disaster or hardware failure, you can instantly failover to the replica and continue your operations.

Asynchronous Replication

Asynchronous replication is usually based on periodic snapshots. Once an initial data copy is created, only the changes that have occurred since the last snapshot are replicated, saving time and bandwidth. This significantly lowers the burden on production storage systems and networks when compared to full data copies.

Another major difference between backup and replication is that you can backup on private clouds and public cloud, while you can only replicate and instantly failover on private clouds. The reason is that real time sync with public clouds simply isn’t possible.

What’s the necessity of Cloud based backup?

There are a number of reasons why enterprises utilize cloud based backup. It depends on the type of data being backed up as there are three major types of data: hot data, cold data and archival data. Hot data is data that is accessed frequently while cold data is accessed infrequently and archival data is the data that has to be archived; generally for compliance reasons and future reference.

For instance, consider the finance industry. Many financial systems require data retention for 7 years and there are big penalties for enterprises that don’t comply. Retention of data that isn’t accessed frequently on local infrastructure is simply not economical and not even feasible. Imagine the hassle of retrieving a single file, 5 years later from your local backup infrastructure. For such archiving purposes cloud backup services are ideal.

Another reason to employ backup is to keep sensitive data from harm. If data is encrypted at source and stored on the cloud, then the cloud service provider cannot read this data. While ransomware may be able to devastate local infrastructure but the backup remains safe and can be restored at any time.

Why you need backup when you have replication

Consider a logical corruption scenario where data has been deleted accidentally or due to malicious intent; then the data has replicated to your replica as well. Replication is simply not helping you there. This implies if a single folder is deleted, you have to initiate a failover just to recover it. Would you initiate a failover just for this purpose? Probably not.

This is the key point why you need to incorporate backup and replication in your backup and disaster recovery plan. Only by having both solutions can you ensure that your data is highly available and your business continuity is flawless.

Having a backup facilitates, you comply with industry regulatory authorities while having a way to restore data when all else fails. It also ensures that your data isn’t completely lost if a malicious attack or accidental data deletion occurs.

Conclusion

Enterprises using replication services may question the necessity of cloud backup. However, a comprehensive backup and DR plan is simply incomplete without the combination of backup and replication. Replication ensures instant failover and business continuity 24/7/365; while backup guarantees that data is always recoverable even in case of a disaster or deletion. This makes backup a key element, despite the acquisition of replication.