Hybrid Cloud Storage: Extending the Storage Infrastructure
Cloud computing has several clear business models. SaaS delivers software, upgrades and maintenance as a service, saving customers money by eliminating costs of ownership that the cloud provider now bears. Several technology factors contribute to SaaS's increasing popularity including protocol standardization, including the ubiquity of Web browsing, access to broadband networks, and rapid application development.
SaaS isn’t perfect – people have legitimate concerns about data security, governance, vendor lock-in, and data portability. But based on its success, the advantages of SaaS seem to be outweighing its challenges. And the market segment is growing fast.
Another cloud computing model is IaaS, where the customer outsources the compute infrastructure to a cloud provider. This model is gaining traction, especially for application development and testing. App developers are able to take the capital they would otherwise have to spend on buying computing gear and target it to specific development projects that are underway in Internet data centers.
The problem with IaaS is that cloud software development doesn’t necessarily translate well into on-premises deployments and many developers prefer to develop SaaS.
Storage in the cloud is yet another business model with different dynamics. While SaaS and Iaas are strongly oriented toward cloud deployments, there are major pressures driving cloud storage toward on-premises deployments.
While storing data in the cloud for SaaS and IaaS computing is certainly important, the vast amount of data still resides on-premises where its growth is largely unchecked. If the cloud storage is going to succeed, it needs to become relevant to the people managing data in corporate on-premises data centers.
The Promise of Hybrid Cloud Storage
Running applications on-premise and using the cloud to store active files is not realistic due to latency and bandwidth issues. On-premise Tier 1 transactional applications with their heavy traffic, high churn rates and high performance I/O are completely out of the ballgame.
However, Tier 2 applications like Exchange, SharePoint and office applications generate the majority of business data. This data quickly ages, resulting in vast stores of dormant data. This environment can strongly benefit from integrating on-premise storage with cloud storage.
The new hybrid cloud storage (HCS) model holds tremendous promise for cost savings around scalability and disaster recovery for busy Tier 2 applications. The idea of HCS is to integrate on-premise storage systems with online cloud storage tiers to extend the infrastructure across on-premises and cloud domains. This enables IT to significantly increase its ROI by lowering on-premises infrastructure costs for long-term storage of Tier 2 application data.
Why is this technology so welcome? Because IT is between a rock and a hard place with Tier 2 application data. The data is growing by leaps and bounds: reaching 60% or greater growth year after year – faster than any other type of business data.
This data growth is extremely costly in terms of storage capacity, power and cooling capacity, and management overhead. Managing the physical plant is only part of the problem as best practices for data protection are also under heavy pressure. Without a different storage approach, many IT organizations are stuck with increasing their annual storage spending, including doubling down to pay for expensive remote DR sites to immediately failover and restore active application data.
HCS solves these challenges by turning the cloud into a functioning storage tier for an on-premise storage system. Hybrid cloud storage preserves on-premise processing speeds for the working set of data on-premises and adds the scalability of the cloud with its controllable costs. A common management interface unifies the on-premise and cloud environments, enabling IT and application admins to view stored data as an integrated unit.
HCS architecture consists of an on-premise storage system built for Tier 2 application requirements. Ideally the system contains SSD cache and SSD storage tiers for highly active data, and SAS disk for fast secondary tiers. The HCS storage system connects to the cloud and enables it to act as a third storage tier for aging application data. The application may freely access the data on the cloud without using backup catalogs or archive restore procedures.
The Problem with Latency
The trick to maintaining the cloud as an active storage tier is compensating for latency. Latency between on-premise and the cloud is a given at the present state of cloud development. The most common Web protocols including REST and SOAP introduce latency, although they are a vast improvement over direct file storage calls over the WAN. When active data is stored on the web and on-premise applications are attempting to interact with it, latency can play havoc with response times.
HCS vendors must compensate for latency in order to integrate cloud storage as an active tier. The industry is in the beginning of developing these capabilities and, despite the challenges, appears to be making real progress.
Storage vendors are actively developing technology to counteract latency’s effects because the business opportunity for integrating on-premise data with cloud data is so compelling. Vendors have been eagerly working from both sides of the divide: the on-premise side employs Web protocols with hybrid appliances and gateways, minimizes data with inline data dedupe and compression, optimizes the WAN, and runs snapshot technology in the cloud as well as the array. Several vendors also map metadata across on-premises and cloud storage to facilitate fast restores from the cloud. Cloud service providers are also enabling the technology with encryption, data integrity scrubbing and in-cloud cloning and remote replication, making multiple cloud instances appear as a single cloud resource to the on-premises processes.