[AlwaysOn] AlwaysOn可用性组的故障转移和故障转移模式[中英文对照] 2

自动故障转移

Automatic failover

在丢失主副本时自动发生的故障转移。仅当当前主副本和一个辅助副本同时配置为使用自动故障转移模式，并且辅助副本当前已同步时，才支持自动故障转移。如果主副本或辅助副本的故障转移模式设置为手动，则不能发生自动故障转移。

A failover that occurs automatically on the loss of the primary replica.   Automatic failover is supported only when the current primary and one   secondary replica are both configured with failover mode set to AUTOMATIC and   the secondary replica currently synchronized. If the failover mode of either   the primary or secondary replica is MANUAL, automatic failover cannot occur.

计划的手动故障转移(无数据丢失)

Planned manual failover   (without data loss)

计划的手动故障转移或“手动故障转移”通常是由数据库管理员为了进行管理而启动的故障转移。仅当主副本和辅助副本同时配置为使用同步提交模式并且辅助副本当前已同步(处于同步状态)时，才支持计划的手动故障转移。当目标辅助副本同步后，即使主副本已崩溃，也可以进行手动故障转移(无数据丢失)，因为辅助数据库已准备好进行故障转移。数据库管理员需要手动启动手动故障转移。

Planned manual failover, or manual failover, is a failover that   is initiated by a database administrator, typically, for administrative   purposes. A planned manual failover is supported only if both the primary   replica and secondary replica are configured for synchronous-commit mode and   the secondary replica is currently synchronized (in the SYNCHRONIZED state). When   the target secondary replica is synchronized, manual failover (without data   loss) is possible even if the primary replica has crashed because the   secondary databases are ready for failover. A database administrator manually   initiates a manual failover.

强制故障转移(可能丢失数据)

Forced failover (with   possible data loss)

当没有任何辅助副本与主副本同步，或者主副本未运行且没有辅助副本准备好进行故障转移时，可由数据库管理员启动的故障转移。强制故障转移存在数据丢失的风险，建议严格限制用于灾难恢复。强制故障转移也称为强制手动故障转移，因为它只能手动启动。这是异步提交可用性模式下支持的唯一故障转移形式。

A failover that can be initiated by a database administrator when no   secondary replica is SYNCHRONIZED with the primary replica or the primary   replica is not running and no secondary replica is failover ready. Forced failover   risks possible data loss and is recommended strictly for disaster recovery.   Forced failover is also known as forced manual failover because it can only   be initiated manually. This is the only form of failover supported by in   asynchronous-commit availability mode.

自动故障转移集

Automatic failover set

在给定的可用性组中，仅当一对可用性副本(包括当前主副本)配置为使用同步提交模式以及自动故障转移(如果有)时，才发生这种故障转移。仅当次要副本当前已与主要副本同步时，自动故障转移集才会生效。

Within a given availability group, a pair of availability replicas   (including the current primary replica) that are configured for   synchronous-commit mode with automatic failover, if any. An automatic   failover set takes effect only if the secondary replica is currently   SYNCHRONIZED with the primary replica.

同步提交故障转移集

Synchronous-commit   failover set

在给定的可用性组中，仅当一组(两个或三个)可用性副本(包括当前主副本)配置为使用同步提交模式(如果有)时，才发生这种故障转移。仅当辅助副本配置为使用手动故障转移模式，并且至少一个辅助副本当前与主要副本同步时，同步提交故障转移集才会生效。

Within a given availability group, a set of two or three availability   replicas (including the current primary replica) that are configured for   synchronous-commit mode, if any. A synchronous-commit failover settakes   effect only if the secondary replicas are configured for manual failover mode   and at least one secondary replica is currently SYNCHRONIZED with the primary   replica.

整个故障转移集

Entire failover set

在给定的可用性组内，其运行状态当前为联机的所有可用性副本的集合，而不考虑可用性模式和故障转移模式。仅在当前没有辅助副本与主要副本同步时，整个故障转移集才会变为相关。

Within a given availability group, the set of all availability replicas   whose operational state is currently ONLINE, regardless of availability mode   and of failover mode. The entire failover setbecomes relevant when no   secondary replica is currently SYNCHRONIZED with the primary replica.