Failures can occur unexpectedly at any time. In such a situation, there has to be some way to ensure that the application is online. Amazon Web Services provides a solution to this problem through the availability zones that have low latency connections are separated from each other. When an application is deployed across various such zones, it can remain online even when an outage occurs at a particular location. N2WS is a Disaster recovery solution provider that makes use of the Amazon Availability zone.
AWS regions is another term that is a group of availability zones associated with the physical data centres in the area. All the regions are separated from one another and remain independently on the basis of location, water supply, power etc.
When there are significant workloads that need data sovereignty and compliance, while assuring that the user data remains in a certain geographic area, this isolation of the AWS regions becomes a prime necessity. There is a minimum of 2 availability zones in each region and the zones are hosted by distinct data centres.
When a Region is available for the AWS customer usage, there is a logical data centre associated with that area which is known as an Availability Zone. In order to ensure the avoidance of the chance of both the zones failing at the same time, there is a distinct networking, power, and connectivity in each zone of the region. This doesn’t mean that one data centre is one zone. In fact, there may be one or more data centres in a zone. A data centre is never shared by 2 zones.
A redundant low-latency private network links is used by the data centres for remaining connected with each other. In this way, communication is possible between the various zones. Various AWS services such as storage and database management make use of intra-zone and inter-zone links for data replication.
The data centre becomes the single failure point when redundant servers run in each tier. This can be avoided by placing virtual servers per tier in every zone. The traffic can be directed to another point when a zone goes offline because of the Amazon Elastic Load Balancers (ELB)present at various application tiers. These ELBs are located outside zones which keeps them safe from any failure of a zone. Among the various AWS services, Elastic Load Balancers has a regional scope and can traverse across the zones in that Region.
