You have migrated your infrastructure to a public or private Cloud, and you think you can stop thinking about an IT continuity plan because your Cloud provider is commited to SLA availability of 99.9%. And that's a common cyber-security mistake.
Moreover, some think, in the same spirit, that migrating to Cloud means not having to backup your data. This is wrong! As well as not checking for your Cloud provider backup policy or Recovery plan when switching your IT to SaaS solution is a really bad idea.
We will explains the risk of all mentioned earlier, but first, let's talk about the many differets Cloud situations:
Set of dedicated hypervisors that do not incorporate intrinsic backup mechanisms
Many areas of availability but does not include automatic failover mechanism
One of the most real cases was the shutdown of the 3 AWS' data centers in New Orleans during 2005 Hurricane Katrina. The effects were very important, Datacenters were stopped several days. This scenario is becoming more real even in France and Europe.
Recently few Clouds have had shutdowns (often related to electrical incidents or telecom interruptions) of several hours, which had impacts on some customers over 24 hours.
Despite precautions implemented in the Cloud (especially the Public Cloud) to put men at distances of infrastructure, unexpected error can happen. To minimize human intervention, administrators work only through controlled configuration deployment. ..
This scenario regularly happens and randomly affects Clients instances, stopping their IT for a few minutes to several hours.