Are hybrid clouds the path to cloud-computing nirvana?

If you’re tackling your company’s computing needs, you’re going to have to look to the clouds. But which ones?

You’ve likely heard of cloud computing — shared computing resources available over the “cloud,” or the Internet. But it turns out there’s more than one way to cloud.

When most people talk about the cloud, they mean a public cloud — big server farms maintained by companies like Rackspace and Amazon.com available to and shared by a wide range of customers. They typically sell storage, bandwidth, and computing power at rates cheaper than most businesses could obtain on their own by maintaining their own computing infrastructure.

There are also cloud applications, like Salesforce.com’s customer-relationship management service, which provide both the software and the computing power needed to run it as a package deal. These, too, are a specialized form of public cloud.

The cost savings are compelling: Why own when you can rent? But cloud computing requires a shift in how programmers design and develop applications, however. That’s a burden for businesses both large and small. Add to that lingering concerns over security and availability, and it’s easy to understand why not everyone’s rushing to the public cloud.

Security concerns with the public cloud are mostly a myth, said Jason Hoffman, founder and chief technology officer of cloud-computing provider Joyent. But most major companies will probably still always have security standards that will prevent them from moving their business into the public cloud. Many businesses don’t want to ship sensitive information off to public cloud servers, especially if they’re in regulated industries. And for time-sensitive tasks like, say, computerized trading, firms may not want to give up the edge they get from running their own servers.

That doesn’t mean companies can’t embrace cloud computing. The notion that the cloud is “all or nothing” is a myth, Amazon.com CTO Werner Vogels, a big public-cloud proponent, said earlier this year.

Some businesses are beginning to set up their own cloud-like pools of computing resources, called private clouds. They use the same kind of over-the-Internet architectures as public clouds, but they’re reserved for the use of the organization and can be firewalled off from the public Internet for a higher level of security and performance.

The best-of-both-worlds mix, where businesses use private clouds for their most important computing tasks and public clouds for occasional peaks of demand or less-sensitive tasks, like serving up images on a website, is the hybrid cloud. And it could be the way forward for businesses that aren’t ready to sail all the way to the cloud.

Startups and big software companies are gearing up for the hybrid-cloud opportunity. Eucalyptus Systems, a startup which recently raised $20 million, is making tools that help businesses adapt their applications to run on hybrid clouds. Microsoft and SAP are increasingly talking about hybrid clouds, where their software is available for installation on customer-owned servers and also provided as a service over the Internet.

Odds are that the public cloud will be the infrastructure that inevitably wins out, especially as the strength of their security gets tested and proven to the satisfaction of customers and regulators. But hybrid clouds could win in the short-term, as a way to get businesses started on cloud architectures. And in some ways they live up to the ultimate promise of cloud computing — that it doesn’t matter where our servers are physically located. Public cloud, private cloud, hybrid cloud — as long as it’s in the cloud, and we’re getting more efficient, we’re headed in the right direction.