Wednesday, 7 January 2009

Redundant Array of Inexpensive Clouds - Pt III

In my two previous articles I discussed Cloud Storage and the concept of using middleware to store multiple copies of data across different service providers. In this final part, I'd like to discuss the whole issue of security.

Using "the cloud" to store data requires a major shift in thinking; traditionally all your information would be stored locally and therefore benefit from the advantage of physical security. Not only would someone need to hack your firewall to get network access, they would then have to obtain system access too, and likely as not would be spotted (hopefully) quite quickly. So, retaining physical access to data has been a significant benefit.

Now we've obviously been trusting a form of cloud storage for some time. Email systems like Gmail, Hotmail and Yahoo have always had access to our email data and have provided limited storage capabilities but they haven't really been the foundation for running a business (although I'm sure there are organisations that have done it). Putting data into the cloud means there's always a risk of someone else getting to your data. You make someone else the guardian or gatekeeper of that data access and rely on the quality of their encryption and access controls. So, it is important to understand what facilities each infrastructure provider offers.

Amazon Web Services

Amazon have a great whitepaper on security, which can be found here. It highlights the level of physical security offered (which is high) plus details of the logical security of data. It may seem surprising that Amazon don't routinely back up data on AWS but rely instead on multiple copies in remote locations, however backup and archive should be thought of as distinct requirements. In addition, data at rest in AWS is not encrypted; users of AWS should therefore ensure their service provider offers this capability at source.


Nirvanix have two white papers which discuss data security. They can be found here (registration required). As with Amazon, Nirvanix are keen to highlight the security of their facilities and adherence to Statement on Auditing Standard (SAS 70) certification. They also go further in indicating that data is stored using RAID-6 and RAID-10 protection, with backups in place too.


Both AWS and Nirvanix offer good physical security and SSL encryption for data in flight. Encryption at rest and backups are not routinely offered and therefore a cloud user should weigh up how these features are to be implemented. This takes us back to the original premise of these postings, the idea of using multiple cloud providers to add resilience and availability to cloud stored data. It also demands a set of standards for cloud storage use, which I am working on even as I write this post. Watch this space.

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