The term “Redundancy” (冗長性) is often misunderstood as a synonym for “Availability” (可用性). Though there is some conceptual overlap, they are not the same. Redundancy refers to the use of multiple servers in a load balancing environment to improve server performance, scale out servers according to increased users, and improve availability. Availability is specific to a multiple server environment designed to continue functioning even when one or more servers fail, and includes features like failover. There are cases where a system with redundancy may not ensure high availability.
- Availability: The ability of an IT service or other configuration item to perform its agreed function when required.
- Redundancy: The practice of using one or more additional configuration items to provide fault tolerance, which may include multiple servers.
- Availability – The ability of an IT service or other configuration item to perform its agreed function when required.
- Redundancy – The practice of using of one or more additional configuration items to provide fault tolerance.
What is Azure Availability Set?
Azure availability sets organize your virtual machines (VMs) into logical groupings. These groupings allow Azure to understand how you have built your application hosted on the virtual machines. Azure can then provide better virtual machine management, redundancy, and availability. Reference link
可用性セットとは、同一データセンター内の別のサーバーラックに配置された仮想マシンを配置する設定のことです。物理サーバーや電源装置、ネットワークスイッチなどラック内で障害が発生しても別ラックに配置された仮想マシンに切り替えることでシステム停止を防ぐことができます。また、保守員によるメンテナンスの際にも、可用性セットを使えば不意の停止を避けることができます。Reference lInk