Hybrid Cloud Backup

Hybrid cloud backup can be described by using the term D2D2C. It defines a backup strategy using a Disk-to-Disk-to-Cloud (or online) storage. In this architecture, data backups stored short-term on local disk storage (disk cache) will eventually be replicated to cloud storage. The combination of Disk-to-Disk backup with online backup is similar to Disk-to-Disk-to-Tape strategy.

It provides a solution which takes advantage of the best of both worlds. Disk to disk backup is ideal for short-term storage. Instead of backing up directly to the cloud, you have these backups locally, which gives you peace of mind.

Because data is backed up first on disk staging, and later replicated to the cloud storage, this model of hybrid backup is not very different from the strategies using tape backup as final destination.

Benefits of hybrid online backup

The main benefit replicating data from the disk cache to the cloud is that you automatically send your data offsite, which is the essential step for resilience and for any disaster recovery solution.

When using tapes, you also have to store data offsite. Actually, there are some steps to be followed: you have to encrypt the tapes, and then ship them offsite. When replacing the backup tapes with cloud backup storage, data is already encrypted as part of the online backup, and you do not need to worry about any physical shipment offsite.

Hybrid cloud backup also simplifies the backup infrastructure, and decreases power, cooling, and physical maintenance requirements. The online storage is highly scalable. From an organization perspective, it can be considered as a storage tier with an unlimited retention period. No data retention policies are needed from your part, no storage management for this online tier.

Hybrid online backup scenarios often provide an on-site appliance, which provides local cache and memory, data deduplication and encryption. Data deduplication technologies ensure that the online storage can store more data while optimizing the data footprint. The technology can provide close to 100% storage utilization by eliminating the massive amounts of unused storage which are always present when using traditional data storage.

Hybrid backup cons

The first would be price, as nowadays tape is the cheapest backup medium available. Even if cloud storage prices are going down, tape still looks unbeatable from this point of view.

There is always a risk whenever you are contracting with a third party. Many people are worried when it comes to handle their data to a service provider. You have to know exactly what are their security models, and how they protect and store your data.

Another disadvantage is that the replication of the first data set taking a long time. Also, recovering data over lower bandwidth can be slow, so you need to compare with the theoretical time required to get tapes back from an offsite location, in case you still think of using tape backup.

If using a backup appliance, in case of failure the recovery of data to the new hardware can be slow depending on the amount of data being restored. And there is the risk of the provider changing ownership, which may lead to change in terms of service.

The combination of disk staging with cloud storage allows for a hybrid backup approach, and offers the flexibility of a tiered data recovery solution.