Getting 99.999% availability and beyond
This recipe will discuss the differences between DR and HA and how to architect HA solutions. Before we get into that, let’s refine the definition of a few key terms:
- High availability, or HA: This means protecting from the failure of a single component. Think of this as protecting against the failure of a system.
- Disaster recovery, or DR: This is the failure of the data center or cloud region.
- Availability nines: When referring to nines of availability, it is a way to quantify the uptime or reliability of a system by specifying the number of nines in the uptime percentage. Each nine represents a decimal place in the uptime percentage.
Here’s a breakdown of the most commonly used nines and their corresponding uptime percentages, assuming 24x7x365 operations:
Nines |
Downtime per Year |
Downtime per Month |
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