Hybrid cloud backup: D2D2C emerging as a viable data backup strategy

Disk-to-disk backup took backup industry by storm, but a new force -- the cloud -- has arrived on the backup scene. Learn how hybrid cloud backup is poised to shake up D2D backup.

Today, the cloud stirs up all manner of possibilities for handling data protection, but the cloud also brings many challenges: security, bandwidth, connection availability and data recovery.

Perhaps in response to these issues, innovators in this space are blending the capabilities of traditional onsite backup systems with cloud storage, so that the best of both worlds is available to users—an onsite component captures and restores data at high speed, while older data is moved to the cloud. Hybrid cloud backup, or disk-to-disk-to-cloud (D2D2C), is turning the cloud into an accessible and useful component of the data protection infrastructure today.


>> What is hybrid cloud backup?
>> D2D2C solutions today
>> Hybrid cloud backup benefits
>> Hybrid cloud caveats
>> The future of hybrid cloud backup

Hybrid cloud backup came about as a way of connecting traditional backups to the cheap, offsite and limitless capacity in the cloud. While a hybrid cloud backup solution may use some amount of disk capacity in the form of local cache, that disk usually only serves as a short-term staging place for data that will soon be sent to the cloud. As data is received, it is stored on disk so that the backup can be captured at high speed, and then either the backup software or a D2D2C appliance encrypts and transmits data to a service provider. Following transmission of the complete backup, the oldest backup data may be discarded to make room for additional backups, while the most recent data is retained to speed data recovery operations.


There are in fact a number of possible hybrid cloud backup tools today, including traditional backup suites that use local disk as a target, and then eventually move data to the cloud. Nearly every backup software vendor has or is working on such a solution today, including the likes of Acronis Inc., CommVault Systems Inc. and Symantec Corp.

But one of the more interesting and recent developments has taken the form of a cloud backup appliance. These appliances will often use dedicated hardware to optimize the amount of transmitted data and reduce the capacity used in the cloud by applying data deduplication, compression, and WAN optimization technologies. These hardware appliances can make backup to the cloud practical over moderate bandwidth internet connections, while also optimizing the on-going costs of cloud storage that is usually priced by the amount of data stored and the amount of data transmitted.

There are a number of general-purpose cloud storage appliances on the market that can be used as a backup target, including appliances from CTERA Networks Ltd., Cirtas Systems, Nasuni Corp., StorSimple Inc. and TwinStrata Inc., and more on the way.  But there are also some dedicated cloud backup storage appliances that may have even better integrations and capabilities for backup - one such example is Riverbed's Whitewater.


Hybrid cloud backup technology brings some compelling promises. Most common is addressing the complexity of offsite data protection. Hybrid cloud backup leverages the existing backup and recovery infrastructure, and seamlessly moves data offsite without requiring additional data copy, tape export, and/or transport activities. Moreover, since most solutions are stateless and can immediately access the cloud data from a new location, they often improve the accessibility of offsite data when it comes to disaster recovery (DR). Some products can even make the data in the cloud accessible by cloud computing applications in the event of a disaster, thereby making cloud-enabled DR a possibility.

Other users will often come to consider hybrid cloud backup in the face of operational constraints, limited physical facilities to support backup system growth, or a desire to decrease power, cooling, or physical maintenance requirements. In this case, hybrid cloud backup can significantly simplify your backup infrastructure, and shed operational costs in exchange for the "pay-as-you-go" pricing of cloud storage.

For each of these types of users, secondary benefits are easily recognized that are often as powerful as the primary benefits they are seeking. One such benefit is the idea of the unlimited retention that the cloud makes possible with its unlimited, almost infinitely scalable capacity. Coupled with the data deduplication technologies common in appliances, the cloud can easily serve as a repository for much more data while optimizing the data footprint for minimal capacity consumption. A complementary benefit is that turning to the cloud for capacity can do away with periodic physical upgrades. This can put an end to painful data migrations.


While the benefits are compelling, most users still regard the cloud with some level of skepticism. However, vendors are working to address some of the concerns around cloud backup; for example, offering encryption for data in transit and at rest to address security concerns.

While the benefits are compelling, most users still regard the cloud with some level of skepticism.

Another issue is the fact that moving backups into the cloud can often take a long time to move the initial data set. While optimization can reduce the total amount of data across multiple backups, the first backup can still be big, and may take some time to copy into the cloud and get fully protected. Similarly, the recovery of data to a new appliance in the event of a disaster or appliance failure can be slow depending on the amount of data being restored. However, a recovery over limited bandwidth may still be faster than trying to obtain offsite tape. Nonetheless, do your diligence and evaluate how a cloud backup strategy supports your recovery time/recovery point objectives.

Hybrid cloud backup should not be assumed to be a complete and easy panacea for traditional remote office data protection challenges. Appliances currently on the market can't access the same storage cloud at the same time, nor can they dedupe across appliances. This means backup from two sites will have reduced efficiency and tie up more bandwidth, and backed up data cannot be easily shared across multiple appliances at different sites. While this can make bandwidth utilization problematic if attempting to backup multiple branch offices through a single main office internet connection, it can also complicate matters if the business requires a single consolidated copy of protected data for e-discovery, compliance or other purposes. In such cases, multiple sets of data in the cloud can't be easily and simultaneously accessed from a single location, and businesses may be better off with a solution that migrates protected data to a centralized data center for consolidated protection and retention. Businesses with multiple locations that also require centralized visibility into protected data may think "access anywhere" cloud storage will simplify their task, only to find that hybrid backup solutions complicate it.


While the hybrid cloud backup technology extremely new, some of its benefits include hands-off management, low cost, flexibility, and built-in DR. These factors are driving this market onward toward significant growth, as highlighted in a recent Taneja Group Emerging Market Forecast, where we have predicted hybrid cloud backup solutions will grow at a CAGR of more than 80% and serve up a good bit more than $300M in backup products in 2014.

About this author:
Jeff Boles is a senior analyst and the director of Taneja Group's hands-on Technology Validation Services, focused on validating vendor solutions in real-world use cases. Prior to his several years with Taneja Group, Jeff's background includes more than 20 years of senior management and hands-on infrastructure engineering within the trenches of operational IT.

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