Cloud Application Architectures

Disasters in the Cloud

Assuming unlimited budget and capabilities, I focus on three key things in disaster recovery planning:

1. Backups and data retention

2. Geographic redundancy

3. Organizational redundancy

If I can take care of those three items, it’s nearly certain I can meet most RPO and RTO needs. But I have never been in a situation in which I had an unlimited budget and capabilities, so I have always had to compromise. As a result, the order of the three items matters. In addition, if your hosting provider is a less-proven organization, organizational redundancy may be more important than geographic redundancy.

Fortunately, the structure of the Amazon cloud makes it very easy to take care of the first and second items. In addition, cloud computing in general makes the third item much easier.

Note

The section contains a lot of content that is specific to the Amazon cloud. Most clouds currently have or are developing concepts similar to EC2 block storage devices and snapshots. For such clouds, many of these concepts apply. Issues relating to geographic redundancy, however, are specific to your cloud provider, so very little that I say on that subject applies to other cloud providers.

Backup Management

In Chapter 4, I looked at the technical details of how to manage AMIs and execute backups in a cloud environment. Now it’s time to take a step back from the technical details and examine the kinds of data you are planning to back up and how it all fits into your overall disaster recovery plan. ...