Cloud Storage: Issues to Consider

Processor Magazine: Cloud Storage: Issues To Consider
Services Offer Attractive Pricing & Great Flexibility, But They Come With Pitfalls

Key Points

• Cloud storage services can provide fully managed capacity at a fraction of the cost most enterprises can procure and operate internal storage infrastructure.

• A lack of standard access protocols and the need to use proprietary APIs means using cloud storage is complex and can make migrating data between cloud vendors difficult.

• Because of inherent WAN performance limitations, cloud storage is ideally suited for static, infrequently accessed information such as archives or applications such as Web 2.0 content that are already in the cloud.

Net-savvy individuals increasingly use online storage to back up their local PCs. These cloud storage services have been joined by a slew of alternatives targeting the enterprise.

But this isn’t such a novel concept. As Burton Group storage analyst Gene Ruth points out, “we’ve been here before,” noting that as early as 2000, Enron attempted to broker online storage. Ruth notes that those fledgling efforts failed primarily because of technological limitations. However, today’s era of fast and cheap Internet bandwidth and voluminous storage systems have changed that.

Cloud storage gets the attention of IT managers with its comparatively low cost and ability to easily adjust capacity. For example, Dragon Slayer Consulting estimates that the so-called “burdened cost of storage,” which encompasses the TCO for storage hardware and associated administration overhead normalized on a per-gigabyte basis, is about $15 per year for an in-house Tier 2 solution (used primarily as secondary storage for unstructured data or backup) vs. $3 per year for a storage delivery network.

A recent report from Gartner examining the benefits, risks, and costs of cloud storage finds a comparable 5.5-to-1 cost advantage for cloud storage providers. Gartner concludes, “End users cannot match cloud storage vendor’s total costs of ownership (TCOs) unless they are willing to build and maintain their own storage solutions.”

Although cloud storage offers some powerful financial incentives, potential customers face a host of technical, integration, security, and organizational issues.

Interoperability & Control

A major source of CIO anxiety, according to Ruth, is an enterprise’s perceived loss of control over data once it’s outside the enterprise’s facilities. Although the concerns are largely hypothetical and psychological rather than actual, he notes that given the immaturity of cloud services and their evolving business model, users can have legitimate concerns about a vendor’s viability and operational processes.

Eran Farajun, executive vice president at Asigra (www.asigra.com), makes a distinction between control of data and custody, arguing that cloud storage maintains user control while offloading day-to-day operational custody of the data. He compares using cloud infrastructure to putting money in a bank vault vs. hiding it under a mattress—customers should use the same diligence when evaluating cloud vendors as they do in vetting financial institutions.

Other concerns Ruth sees include the difficulties of monitoring compliance with service levels, the need for data migration contingencies should the vendor violate SLAs, and legal or regulatory ambiguities when using shared storage.

The complexity of actually using cloud storage is something Gartner principal analyst Adam Couture says many customers underestimate: “It’s not plug-and-play.” He notes that each vendor has different access methods involving custom, nonstandard APIs that make integrating applications such as archiving or file shares with cloud storage difficult and costly. Couture is aware of one large enterprise that spent $250,000 on custom programming to get a particular application and its data onto a cloud service.

In general, using cloud storage isn’t as simple as plugging in a NAS device and mapping a network drive. Couture notes that some vendors provide software clients that implement common network file sharing protocols such as NFS or CIFS, but these are proprietary and cannot bridge between different cloud services. The lack of standard protocols for accessing cloud storage means there is no interoperability between cloud storage providers, greatly complicating data migration, which Ruth says can easily lead to vendor lock-in.

Performance & Security

Access to cloud data is inherently limited by network throughput and latency, and despite dramatic improvements in Internet performance, it still pales in comparison to a local SAN. Although some vendors attempt to enhance throughput with various local caching and compression techniques such as those used for WAN acceleration or content delivery networks, as Ruth points out, these don’t improve Internet latency.

Gartner’s Couture considers data security as the biggest issue with cloud storage. Given the leakage potential, both in transit and within a shared infrastructure, experts agree that using encryption on all data stored in a cloud is essential, although, depending on the application, this is easier said than done. Ruth notes that unlike consumer-oriented products, enterprise storage services typically leave encryption setup and management to the customer. However, as Couture cautions, managing encryption keys is not to be taken lightly and can be an administrative nightmare.

Applications For Cloud Storage

When considering applications for cloud storage, Farajun says it’s important to understand the nature of the data being stored. He categorizes four levels based on activity, persistence, and availability (see the “Stages Of Stored Data” chart) and feels more static, inactive data, such as applications that include online backup and archiving, is the best fit for cloud storage.

Couture agrees that archiving works well in the cloud because the data changes less frequently; doesn’t require high-speed, transactional access; can be easily compressed using data reduction technologies such as differential backups and deduplication; and can be easily encrypted in bulk. Archiving software increasingly integrates cloud support directly into the product, which makes using cloud services and data encryption much simpler.

Other potential applications for cloud storage include content delivery of rich media such as video, audio, or image-rich files on a global scale; data for collaboration or Web 2.0 applications; and user file or email repositories. Greg Schulz, principal analyst at StorageIO, summarizes the sweet spot for cloud storage as any application with low I/O performance, a focus on driving down cost, and tolerance for occasional downtime.

Although public cloud-based services have run off scale on the hype meter, cloud storage can have tangible business benefits by quickly reducing an IT department’s CAPEX budget while providing what Asigra’s Farajun describes as “elasticity” in provisioning capacity.

All experts emphasize that anyone considering a cloud service needs to thoroughly understand the vendor’s service levels, pricing plans, data access methods, and operational and security processes, while also having contingency plans for data migration should the enterprise eventually wish to change vendors.

by Kurt Marko
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