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The Challenges of Building Hybrid Clouds

Wikibon Analyst

David Floyer


Building hybrid clouds is in its early stages, and normally requires gateways (e.g., cloud storage gateways) and translation software to connect radically different cloud environments. In this research, Wikibon is testing the premise that effective hybrid clouds will require much greater commonality and convergence of hardware and software within the hybrid cloud segments.

Hybrid Cloud Fundamentals

Wikibon believes the future of enterprise computing is Hybrid clouds, with cloud segments including any combination of:

  • True Private Cloud for on-premise computing;
  • IaaS public cloud computing to support mobile, shared data, development, new applications and “irregular computing”;
  • SaaS clouds for outsourced packages and business processes;
  • “Edge” True Private Clouds for latency sensitive IoT data capture and processing.

Core challenges of hybrid cloud are the transmission and translation of data to and from one cloud to another cloud. Questions include:

  • “What are costs of transmission?”
  • “What are costs of translation between clouds (gateways, entrance and exit “taxes” into and out of clouds?”
  • “Which is the master copy of data?”
  • “Which cloud is responsible for data integrity?”
  • “How are data discrepancies between clouds resolved?”
  • “How are cross-cloud hybrid de-duplicattion and encryption achieved?”
  • “How are functional and maintenance updates managed across a Hybrid cloud?”
  • and many others…

These questions become more important the greater the inter-dependency between the sets of data in the hybrid clouds. It matters much more for hybrid database deployment than historical archiving of PC data.

Transmission costs are significant. Most cloud services do not charge for transmission into the cloud from their closest site. However, all cloud services charge an exit fee for data going out of their cloud. The telecommunication companies also have to be paid for transmission  both in and out of the cloud.

The translation processes are also complex and costly.  The only exception to this complexity and cost  is when all the data is completely managed by one cloud, or having the same software and technology components in all the clouds that make up the hybrid cloud.

The three case studies below look at different hybrid solution architectures, and the impact of reducing the complexity of hybrid cloud architectures.

Traditional Backup Appliances & Software Hybrid Cloud

Figure 1 shows traditional on-premise backup appliances and filers, backing up to one or more clouds.

Figure 1 – Traditional Hybrid Cloud
Sources: © Wikibon 2017.


Table 1 – Software Costs for “Translation” of Traditional Hybrid Cloud to Public Clouds.
Sources: © Wikibon 2017.

The different architecture and software in the different clouds means a requirement for gateways to “translate” data from one cloud to another. There are both hardware and additional software costs for this translation layer. Table 1 shows examples of the additional costs of translating the data from on-premise backup appliances and filers to the cloud. The average 3-year cost of this translation layer is about $2,300 per terabyte list price, and $1,150 assuming a 50% discount. In addition to the additional software costs, there are the costs of storage and systems administration in maintaining the different sets of software, and ensuring data integrity across the on-premise hardware and software, the gateways, and the cloud hardware and software. There is no “one throat to choke” with this approach.

Bottom Line: First generation hybrid clouds use different hardware and software in each hybrid cloud segment, and need gateways. The result is a complex environment, with difficulties to add functionality and maintain existing functionality, and with high entry costs. There is no single throat to choke for enterprise IT management, with additional IT support resources required to maintain availability and integrity.

Avere NAS Hybrid Cloud

Avere supports global file systems with FXT NAS filers on-premise and virtual FXT NAS filers in the cloud, as well as edge cache filers. Avere excels as both a caching device and a global namespace, but it is not a high-bandwidth NAS appliance for heavy-duty workloads. The hardware architecture is of course very different between on-premise appliances and the public cloud services.

To illustrate the complexity, the Avere on-premise FXT filers offer immediate consistency for their global file systems. The Avere FXT virtual NAS filers use Amazon Web Services (AWS) S3 object file for its file storage. However, the S3 service offers eventual consistency, not immediate consistency. When an update is made to a file held in S3, a new object with the update is created and written. However, the S3 metadata is not updated immediately, and the eventual consistency is up to 20 seconds later. That delay is not a significant problem for purely archive applications, but a significant problem for global file systems that require real-time or near real-time data consistency. Avere has had to add significant coding and invention to ensure  immediate consistency across their hybrid cloud file system.

Bottom Line: Avere have put together a second generation sophisticated hybrid cloud solution by using the same software architecture in all hybrid cloud segments. Avere has overcome architectural differences with complex software solutions. Enterprise IT management has a single throat to choke, but separate accounting for on-premise and cloud services.

Oracle ZFS Appliance Hybrid Cloud 

Oracle have taken a different approach to cloud computing in general. Their strategy is to have exactly the same hardware and software on-premise and in the Oracle cloud. For example, the Oracle Cloud Machine runs exactly the same hardware and software stack on-premise as is run in the Oracle cloud.

In March 2017, Oracle announced the same approach for cloud-converged storage. Having identical hardware and software for all hybrid cloud segments eliminates the need for gateways, as Figure 2 below illustrates. The advantage of this approach is that Oracle can architect solutions using the same architecture, metadata structure and hardware both on-premise and in the cloud. This creates a much firmer basis for end-to-end management, and much easier solutions for master copy management, snapshot management, cross-cloud catalogs, elimination of translation between cloud segments, cross-cloud data integrity, cross-cloud data consistency and end-to-end de-duplication and encryption services.

In addition, the IT enterprise should enjoy significantly lower cost of upgrading functionality and maintaining hardware and software levels. Oracle is also in a good position to offer converged pricing on its on-premise and cloud solutions, assuming that Oracle can solve its organization challenges.

Figure 2 – Oracle Cloud-Converged Storage: Hybrid Cloud with Identical Hardware & Software
Sources: © Wikibon 2017.

The disadvantages of the Oracle solution (as of April 2017) are that Oracle does not yet offer NAS solutions and functionality such as global files systems that are offered by Avere and other long-term NAS suppliers such as NetApp. However, the fundamental simplicity of the Oracle Cloud-converged architecture offers Oracle a way to rapidly develop and extend true hybrid cloud solutions. Wikibon expect Oracle to introduce scaleable global file capabilities in their Hybrid Cloud-converged later in 2017.


The basic economics that are driving IT to converged on-premise solutions will drive the requirement for increased commonality and convergence of hybrid cloud components, an end-to-end hybrid cloud architecture, and a “single hand to shake, single throat to choke” delivery and support approach. Wikibon expects SaaS vendors to also provide converged  hybrid cloud solutions.

Wikibon believes that vendors that embrace the converging of their public cloud services with their on-premise appliances and systems are likely to be the major players in the hybrid cloud market. This capability is a potential game-changer. Oracle is well placed with its ZFS cloud-converged and the Oracle Cloud Machine hybrid cloud products, and Wikibon believes there will be more hybrid cloud products using the same approach. Oracle also has a large SaaS base which can also be migrated to a hybrid cloud implementation.

Wikibon also expects public cloud vendors to offer on-premise solutions with the same architecture and software as in their cloud services. Microsoft Azure will almost certainly utilize the Azure stack, and will work with vendors that support and market the Azure stack. Wikibon expects AWS to offer on-premise data services solutions for private clouds, based on AWS public cloud data services in the 2017/2018 timeframe.

Action Item

IT senior management should work with vendors that offer hybrid cloud solutions with as much commonality of architecture and hardware/software components as possible.

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