High Availability
IT resource disruption has a huge
negative impact on any business.
Lost control of the underlying infrastructure
when moving to the cloud,
and the fact than the service-level
agreement (SLA) won’t cover all the
incurred costs, should lead you to design
with outages and high availability
in mind. With the ease of creating
virtual instances, deploying clusters
of servers or services is a popular
approach. In this scenario, load
balancing is a well-established technique
for operating with clusters;
it’s an important feature to consider
when selecting a cloud provider.
It’s also important to use several
available zones or at least different
datacenters to make your system as
robust as possible. Amazon Web Services
(AWS) experienced this in April
2011 when its systems didn’t run
or ran intermittently for four days.
Separating clusters into regions and
datacenters will increase your resources’
resilience.