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Private storage clouds might seem like a rehash of old technology and even older ideas, but there are significant potential benefits once you cut through the hype. Here's what you need to know to get started.
Metaphors for cloud storage may be overused, but we can still relate to the notion that clouds obscure vision and can be either beneficial or turbulent. Both conditions can certainly apply to private cloud storage. Although a lot of the hype around private cloud storage promises all the benefits of a public cloud behind a firewall, private cloud storage really boils down to a new name for utility storage.
Utility storage suffered from its association with selective outsourcing in the post dot-com bust period, even though it's just about simple, certain availability. The name "utility storage" also lacks cachet -- it sounds more like a place to stash your garden tools than a sleek, sexy storage array. "Utility" just doesn't sound as cool as "cloud."
What public cloud tells us about private cloud
The name change doesn't alter the fundamental aspects of the technology being a storage infrastructure designed to provide better service levels with less effort and lower cost. And you can't deny the benefits an IT organization can gain from adopting private cloud concepts, regardless of what label is currently popular. To some extent, though, private cloud marketing catches a ride on the coattails of public
To put private cloud storage into perspective, consider the benefits of public cloud storage:
- Availability. Capacity should be available for immediate provisioning, always on and include swift, certain recovery.
- Quality of service. Service levels should be clearly described and aligned with a services catalog. Tangible metrics should define what users can expect in terms of response time, recovery time and uptime.
- Cost certainty. The per-unit cost of storage in a cloud environment is usually available according to a price list. Users pay for what's actually used, not what's provisioned or the high-water mark, depending upon the service-level agreement.
Looking at that list, there are definitely some significant benefits, but benefits to whom? Therein lies the first key difference between public and private cloud storage. In a public cloud, these benefits accrue to the user and contracting organization as one in the same. Users get all the application support benefits, while the organization gets cost certainty and perhaps a lower cost than that of maintaining an internal infrastructure. But in a private cloud environment, only the app user gains any of these benefits. The IT organization must provide what's essentially platform-as-a-service functionality. While the business unit may gain cost certainty, pay-as-you-go chargeback and concrete service-level agreements (SLAs), none of these benefits flows to the IT organization. They must procure and manage just as much storage, establish the monitoring systems and implement disciplined cost accounting.
This was first published in July 2011