Availability refers to the measure of time that a system or service is operational and accessible to users. It is typically expressed as a percentage, indicating the proportion of time that the service is available over a given period.
SLA (Service Level Agreement) is a contract between a service provider and a customer that outlines the level of service expected. SLAs often include metrics such as availability, response time, and resolution time, along with penalties for failing to meet agreed-upon targets.
Uptime refers to the duration during which a system or service is operational and available to users. It is the opposite of downtime and is often used interchangeably with availability.
Downtime is the period when a system or service is unavailable or not functioning as expected. Downtime can result from various factors such as maintenance, hardware failures, software issues, or network outages.
Together, these concepts form the foundation for measuring and ensuring the reliability and performance of systems and services. By setting and adhering to SLAs, organizations can establish clear expectations for availability, uptime, and response times, thereby providing a better experience for their customers and users.
Additionally, monitoring uptime and downtime allows organizations to identify areas for improvement and implement measures to enhance reliability and minimize disruptions.
A quick cheat cheat on different availability levels i.e 5 9s and what it represents in terms of downtime per year can be found following this link