Review: HP Cloud challenges Amazon and Google

The machines toss in additional disk space. I don't know if this is as important because HP offers other ways of storing information. The virtual machines are disposable, and you shouldn't plan on doing much besides using the disk on them as a cache. You have to back up everything -- HP has a number of options for that.

Ephemeral machines and persistent storage
The traditional idea has always been to separate data storage into a Web service that stands apart from your machine. Amazon S3 pioneered the idea of creating a storage service where you can park your bags of bits. The system is meant to be independent from the compute nodes. Any computer can request copies of any bag of bits whenever it's needed.

HP has its version of Amazon S3 that it calls HP Cloud Object Storage. Like Amazon, HP provides a RESTful API for storing and retrieving files.

As part of the Web management GUI, HP also provides a Web interface for organizing these objects into containers and controlling who can see them. You can upload your files directly from here, then turn on public access. The browser computes the URL for you. It's a nice feature that makes developing and debugging a bit easier than in Amazon, for example. You're not always scrounging around for an FTP password.

HP also included a few tools that make building bigger networks easier. For instance, there's a way to predefine which ports will be open on your new machine, saving you the time of logging into each machine to run a script. HP will load up the right public keys so that you can log in quickly if needed.

The HP Cloud comes with a CDN (content delivery network) built into this object store. If you tap the right button on the Web GUI, the data in a particular container is pushed out into what looks like Akamai's network, at least judging from the URLs. The data is available via an HTTP or HTTPS URL, both nicely added to the Web interface.

The prices begin at 12 cents per gigabyte per month for basic storage and drop as you store more, although the price breaks don't start until you squirrel away at least 10 terabytes. You'll also be billed a penny per gigabyte for every 10,000 requests to store, fetch, or copy your information.

The bandwidth going into the storage cloud is free, but it will cost you to get your data out. After the first (free) gigabyte, it's 12 cents per gigabyte. If you turn on the CDN, the prices jump to 16 cents in North America and more elsewhere.

The object storage is nice, but the most intriguing feature to me is the persistent block storage, a feature that's in a private beta testing phase. The plan is to create virtual persistent disks you can mount on your virtual machines just like a real disk.

With HP Cloud Block Storage, you write to the file system and HP's machines will do the rest. You don't need to write new storage code that only works in the cloud. You just take the code that works with your software and point it toward the block storage partition. HP touts this as a way to easily move information between your instances or keep the data handy when there's no machine using it. You might put your database in the block storage and only connect it to a running instance when you need it.