A couple weeks ago, I delved into the challenges of trying to use the cloud to replace tape for traditional on-premises backup. Although cloud backup can replace tape for small businesses or larger IT departments without long-term retention requirements, enterprises will rarely be able to consider cloud backup as a tape replacement.
When you do the math, it's pretty clear why: A typical enterprise that tries to replace its tape backup systems with cloud storage will either fail to find the connectivity it needs or end up paying substantially more money in the long run as cloud-hosted archival backups and backup-related connectivity fees pile up.
However, simply because the cloud isn't quite ready to replace tape for all time doesn't mean it can't still play an important role in protecting an enterprise's data. Seeing what role cloud backup can play involves putting together a short list of what cloud storage does and doesn't do well. Here, I cover what Amazon.com S3 and Glacier services can do, but much also applies to other cloud storage providers. Don't assume Amazon is the right vendor for you, but it helps to have a clear example.
Reliability: A plus for the cloud
It might seem strange to lead with reliability when talking about the cloud. You're more likely to hear horror stories about cloud service reliability around outages and lost data.
However, when you consider the durability and availability of object storage services such as Amazon's S3 (versus less reliable primary storage services like EBS or EC2 instance storage), you'll see a different story. Amazon says that S3 is designed to provide a data durability of 99.999999999 percent per year. This means that 0.000000001 percent of the objects you store with it will be lost per year. In an example Amazon provides, a company storing 10,000 objects in S3 can expect to lose one object every 10 million years. Or if you're not big on statistics: It's incredibly durable compared to just about any type of storage media you can imagine or could economically construct on your own.