[AlwaysOn] AlwaysOn可用性組的故障轉移和故障轉移模式[中英文對照] 1

備註

Remarks

在資料庫級別，諸如因資料檔案丟失而使資料庫成為可疑資料庫、刪除資料庫或事務日誌損壞之類的資料庫問題不會導致可用性組進行故障轉移。

Issues at the database level, such as a database becoming suspect due to   the loss of a data file, deletion of a database, or corruption of a   transaction log, do not cause an availability group to failover.

在故障轉移期間，故障轉移目標將接管主角色、恢復其資料庫並且使它們作為新的主資料庫處於聯機狀態。以前的主副本一旦可用將切換為輔助角色，並且其資料庫成為輔助資料庫。在可能的情況下，這些角色可以來回切換(或切換為不同的故障轉移目標)，以應對多次故障或滿足管理的需要。

During the failover, the failover target takes over the primary role,   recovers its databases, and brings them online as the new primary databases. The   former primary replica, when available, switches to the secondary role, and   its databases become secondary databases. Potentially, these roles can switch   back and forth (or to a different failover target) in response to multiple   failures or for administrative purposes.

“ 故障轉移模式”屬性指定某一給定可用性副本支援的故障轉移形式。對於某一給定的可用性副本，可能的故障轉移模式取決於該副本的 可用性模式，如下所示：

The form(s) of failover that a given availability replica supports is   specified by the failover mode property.For a given availability   replica, the possible failover modes depends on the availability   mode of the replica, as follows:

·        同步提交副本支援兩種設定：自動或手動。“自動”設定支援自動故障轉移和手動故障轉移。為了防止丟失資料，自動故障轉移和計劃的故障轉移要求故障轉移目標為同步提交的輔助副本且處於正常同步狀態(這表示故障轉移目標上的每個輔助資料庫與相應的主資料庫同步)。只要某一輔助副本不滿足這兩個條件，它就僅支援強制故障轉移。請注意， 強制故障轉移還支援角色處於“正在解析”狀態的副本。

·        Synchronous-commit replicas support two settings-automatic or manual. The   "automatic" setting supports both automatic failover and manual   failover. To prevent data loss, automatic failover and planned failover   require that the failover target be a synchronous-commit secondary replica   with a healthy synchronization state (this indicates that every secondary   database on the failover target is synchronized with its corresponding   primary database). Whenever a secondary replica does not meet both of these   conditions, it supports only forced failover. Note that forced failover is   also supported a replicas whose role is in the RESOLVING state.

·        非同步提交副本 僅支援手動故障轉移模式。此外，因為它們永遠不會同步，所以它們僅支援強制故障轉移。

·        Asynchronous-commit replicas support only the manual failover mode. Moreover,   because they are never synchronized, they support only forced failover.

備註

Remarks

故障轉移後，需要訪問主資料庫的客戶端應用程式必須連線到新的主副本。此外，如果新的輔助副本配置為允許只讀訪問，則只讀客戶端應用程式可以連線到它。有關客戶端如何連線到可用性組的資訊，請參閱 。

After a failover, client applications that need to access the primary   databases must connect to the new primary replica. Also, if the new secondary   replica is configured to allow read-only access, read-only client   applications can connect to it. For information about how clients connect to   an availability group, see .