It's just like an unformatted hard drive, Amazon.com Chief Technology Officer Werner Vogels explained. The difference is that it's in the "cloud" somewhere and you get to it through an API.
Amazon Web Services executives on Sunday described a forthcoming persistent storage feature, called EC2 Persistent Storage, which they say will make its hosted computing services more flexible and far more reliable.
People can sign up for an early beta test program now before Amazon opens it up for a wider release later this year.
The service works with Amazon's Elastic Compute Cloud (EC2) hosted server offering. It allows developers to set aside a storage volume online, on which people save files in different file systems. This differs from what is available now with EC2 because once a compute instance is taken offline, the data associated with it goes away.
With a persistent storage service, data can remain linked to a specific computing instance. Significantly, people can take a snapshot of that data and store it on Amazon's S3 storage service. That effectively acts as a way to create a back-up of their computing operation on the "cloud," according to Amazon executives.
"The snapshot is extremely powerful technology and allows for building highly fault-tolerant applications operating worldwide. Combine these snapshots with Availability Zones and Elastic IPs and you have all the tools to manage and migrate even the most complex of applications," Vogels wrote on his blog.
"And the great thing is it that it is all done with using standard technologies such that you can use this with any kind of application, middleware or any infrastructure software, whether it is legacy or brand new," he added.
Amazon Web Services evangelist Jeff Barr also describes the service on his blog, saying it was one of the most requested features from developers.
Thorsten vok Eiken at RightScale, who has been testing the service, talks about the implications of this feature and says his company is making tools to make it easier to use these services.
Von Eiken says that persistent storage is a dramatically important feature that will lead many more companies and developers to hosted development platforms.
"It's going to be like agile software development: if you want to survive as an Internet/Web service you will have to compute in the cloud or your competitors will leave you in the dust by being able to deploy faster, better, and cheaper," he said.