A series of tests were conducted by storage vendor Nasuni. What they found is quite shocking. The results of the tests indicate that both rival cloud services, MS Azure and Rackspace, are slow to accept data. Whether this is a limitation of the network or a limitation of the hardware, we can not be sure.
Nasuni conducted five series of tests. The results are, again, quite shocking. Since all of these systems are cloud storage, you would expect similar performance, but you would be wrong. For example, moving 12TB from Amazon to Azure takes 40 hours, whereas moving the same data back took only four. 12TB from Rackspace to Amazon took five hours, yet Amazon to Rackspace took almost an entire week! Amazon "bucket" to Amazon "bucket" took only four hours.
Once again, it's not clear if this is just a limitation of the network, or if there is a massive difference in technology that is leading to these poor write speeds. Nasuni said the cloud providers were not "forthcoming about why their performance would vary so greatly." However, "Nasuni did not experience the same behavior with Amazon S3, and this measurement probably further indicates limitations in Azure's architecture or bandwidth, as other customers using the system appear to be affecting our results to a large degree."