什麼是 Azure 中的可用性區域？What are Availability Zones in Azure?

• 10/17/2019
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「可用性區域」是高可用性供應項目，可保護您的應用程式和資料不受資料中心故障影響。Availability Zones is a high-availability offering that protects your applications and data from datacenter failures. 「可用性區域」是 Azure 地區內獨特的實體位置。Availability Zones are unique physical locations within an Azure region. 每個區域皆由一或多個配備獨立電力、冷卻系統及網路的資料中心所組成。Each zone is made up of one or more datacenters equipped with independent power, cooling, and networking. 若要確保復原能力，在所有已啟用的地區中都至少要有三個個別的區域。To ensure resiliency, there’s a minimum of three separate zones in all enabled regions. 地區內「可用性區域」的實體區隔可保護應用程式和資料不受資料中心故障影響。The physical separation of Availability Zones within a region protects applications and data from datacenter failures. 區域備援服務會將應用程式和資料複寫至所有「可用性區域」，以防出現單一失敗點。Zone-redundant services replicate your applications and data across Availability Zones to protect from single-points-of-failure. 使用「可用性區域」時，Azure 可提供業界最佳的 99.99% VM 執行時間 SLA。With Availability Zones, Azure offers industry best 99.99% VM uptime SLA. 完整 Azure SLA 說明保證的 Azure 整體可用性。The full Azure SLA explains the guaranteed availability of Azure as a whole.

Azure 區域中的可用性區域是由容錯網域和更新網域組成。An Availability Zone in an Azure region is a combination of a fault domain and an update domain. 例如，如果您在 Azure 區域中建立橫跨三個區域的三個 (或更多) VM，您的 VM 會有效地分散到三個容錯網域和三個更新網域。For example, if you create three or more VMs across three zones in an Azure region, your VMs are effectively distributed across three fault domains and three update domains. Azure 平台會從更新網域中辨識此分佈，以確定不會同時更新不同區域中的 VM。The Azure platform recognizes this distribution across update domains to make sure that VMs in different zones are not updated at the same time.

藉由將運算、儲存體、網路及資料資源共置於某個區域內並複寫至其他區域，即可讓您的應用程式架構內建高可用性。Build high-availability into your application architecture by co-locating your compute, storage, networking, and data resources within a zone and replicating in other zones. 支援「可用性區域」的 Azure 服務分成兩個類別：Azure services that support Availability Zones fall into two categories:

• 區域服務–您可以將資源釘選到特定區域（例如虛擬機器、受控磁片、標準 IP 位址），或Zonal services – you pin the resource to a specific zone (for example, virtual machines, managed disks, Standard IP addresses), or
• 區域備援服務 – 平台會自動跨區域複寫 (例如區域備援儲存體、SQL Database)。Zone-redundant services – platform replicates automatically across zones (for example, zone-redundant storage, SQL Database).

若要在 Azure 上達到全面性的商務持續性，請使用「可用性區域」與 Azure 地區配對的組合來建置您的應用程式架構。To achieve comprehensive business continuity on Azure, build your application architecture using the combination of Availability Zones with Azure region pairs. 您可以使用 Azure 地區內的「可用性區域」來同步複寫應用程式和資料以提供高可用性，並以非同步方式跨 Azure 地區複寫以提供災害復原保護。You can synchronously replicate your applications and data using Availability Zones within an Azure region for high-availability and asynchronously replicate across Azure regions for disaster recovery protection.

依區域的服務支援Services support by region

支援可用性區域的 Azure 服務和區域的組合包括：The combinations of Azure services and regions that support Availability Zones are:

服務復原Services resiliency

所有 Azure 管理服務的架構都可以從區域層級失敗中復原。All Azure management services are architected to be resilient from region-level failures. 在失敗的範圍中，區域內的一個或多個可用性區域失敗，與整個區域失敗相比，其失敗半徑較小。In the spectrum of failures, one or more Availability Zone failures within a region have a smaller failure radius compared to an entire region failure. Azure 可以從區域內或從另一個 Azure 區域中的管理服務區域層級失敗中復原。Azure can recover from a zone-level failure of management services within the region or from another Azure region. Azure 會在區域內一次執行一個區域的重要維護，以避免影響在某個區域內可用性區域部署之客戶資源的任何失敗。Azure performs critical maintenance one zone at a time within a region, to prevent any failures impacting customer resources deployed across Availability Zones within a region.

PricingPricing

針對部署在「可用性區域」中的虛擬機器並不會產生額外費用。There is no additional cost for virtual machines deployed in an Availability Zone. 有兩部 (或以上) VM 部署在 Azure 區域內兩個以上的「可用性區域」中時，即可提供 99.99% VM 執行時間 SLA。99.99% VM uptime SLA is offered when two or more VMs are deployed across two or more Availability Zones within an Azure region. 在可用性區域之間將額外產生 VM 對 VM 的資料傳輸費用。There will be additional inter-Availability Zone VM-to-VM data transfer charges. 如需詳細資訊，請檢閱頻寬定價頁面。For more information, review the Bandwidth pricing page.

開始使用可用性區域Get started with Availability Zones

• 建立虛擬機器Create a virtual machine
• 使用 PowerShell 來新增受控磁碟Add a Managed Disk using PowerShell
• 建立區域備援虛擬機器擴展集Create a zone redundant virtual machine scale set
• 使用具有區域備援前端的標準 Load Balancer 來進行跨區域的 VM 負載平衡Load balance VMs across zones using a Standard Load Balancer with a zone-redundant frontend
• 使用具有區域前端的標準 Load Balancer 來進行區域內的 VM 負載平衡Load balance VMs within a zone using a Standard Load Balancer with a zonal frontend
• 區域備援儲存體Zone-redundant storage
• SQL DatabaseSQL Database
• 事件中樞地理災害復原Event Hubs geo-disaster recovery
• 服務匯流排地理災害復原Service Bus geo-disaster recovery
• 建立區域備援虛擬網路閘道Create a zone-redundant virtual network gateway
• 為 Azure Cosmos DB 新增區域多餘區域Add zone redundant region for Azure Cosmos DB
• 消費者入門 Azure Cache for Redis 可用性區域Getting Started Azure Cache for Redis Availability Zones
• 建立 Azure Active Directory Domain Services 實例Create an Azure Active Directory Domain Services instance
• 建立使用可用性區域的 Azure Kubernetes Service （AKS）叢集Create an Azure Kubernetes Service (AKS) cluster that uses Availability Zones

後續步驟Next steps

• 快速入門範本Quickstart templates