Review: Rackspace Cloud keeps IaaS simple

The biggest change in the second generation is the file storage that can now live separately from your servers. In the past, the instances were more like real boxes. If you wanted to get the data on and off the machines, it was up to you. Now Rackspace offers storage blocks that are configured separately from your virtual machine. They're mounted like an external disk drive, and you can use them to read and write data apart from your server image.

The block storage API is pretty transparent. After I pushed the button to create the block storage and attach it to my server, I needed to partition, format, and mount the space using the operating system. It's like attaching a storage device to your own physical machine. You get to push the buttons yourself.

Rackspace also offers a very fast SSD option if you want to pay for a bit more speed. The old-fashioned SATA storage is 15 cents per gigabyte per month, while the solid-state storage is 70 cents per gigabyte per month. If you need only a small amount of fast storage, it's a good choice.

There are hints that Rackspace is embracing some of the more amorphous visions for the cloud. If your data needs to reach a wide audience, you can have a slice of Akamai's Content Distribution Network called CloudFiles. You store your data in CloudFiles and Akamai will deliver it faster. Storage is 10 cents per gigabyte per month, while outgoing bandwidth is 18 cents per gigabyte.

The OpenStack advantage
Rackspace was one of the main forces behind OpenStack, and the company continues to make the flexibility of the open source cloud stack one of its big selling points. Your enterprise won't be locked into the Rackspace cloud because you can always set up OpenStack in your own data center -- if and when you want to leave Rackspace behind. This flexibility is crucial for many businesses because rewriting code can be quite a pain, especially if it's older code that someone wrote long ago before quitting.

Rackspace brags that it's not just offering you a separate fork of OpenStack, but the actual code running on its cloud machines. "The software is not a separate distribution of OpenStack, so you don't have to worry about a branching dead end," promises the Rackspace website. This is quite an offer and one that's designed to prey on any enterprise manager's worst fears of vendor lock-in.

Rackspace also pushes hybrid architectures that make it possible for you to link up your private cloud with the Rackspace cloud for moments when you need more servers. One customer, for instance, says it turns on servers in the public cloud whenever it runs major ad campaigns. When the traffic surge is over, the website retreats to the private cloud. Running the same OpenStack layer in your data center makes it simpler to do this.

Rackspace is taking a different approach to storing data. While Amazon, Google, HP, and a few others are building elaborate NoSQL abstraction layers that promise elastic scalability, Rackspace is sticking with MySQL, the decades-old, tried-and-true solution to storing information.