--- title: "角色切换与解耦 - 安装部署工具 OBD V3.6.0 | OceanBase 文档中心" description: 角色切换与解耦 OceanBase 集群的租户角色分为主租户（PRIMARY）和备租户（STANDBY），本文介绍如何使用 obd 动态改变租户角色，以及如何对主备租户解耦。 概念介绍 OceanBase 集群的租户角色包括两种：主租户（PRIMARY）和备租户（STANDBY）。正常情况下创建的普通租户角色均为主租… --- 切换语言 - 中文站 - 简体中文 - International - English - 日本站 - 日本語 文档反馈![](https://mdn.alipayobjects.com/huamei_22khvb/afts/img/A*Qq8pT6yBPTcAAAAAAAAAAAAADiGDAQ/original) 安装部署工具 OBDV 3.6.0 # 角色切换与解耦 更新时间：2026-04-15 16:30:37 [编辑](https://github.com/oceanbase/obd-doc/edit/V3.6.0/zh-CN/400.user-guide/300.command-line-operations/300.manage-cluster/800.physical-standby-database/200.role-switching.md) OceanBase 集群的租户角色分为主租户（PRIMARY）和备租户（STANDBY），本文介绍如何使用 obd 动态改变租户角色，以及如何对主备租户解耦。 ## 概念介绍 OceanBase 集群的租户角色包括两种：主租户（PRIMARY）和备租户（STANDBY）。正常情况下创建的普通租户角色均为主租户，使用物理备库方式创建的租户角色为备租户。 obd 支持通过命令动态改变租户角色。 - Switchover Switchover 操作是在用户计划内对租户角色进行变更。执行 Switchover 操作后，主租户会与对应的备租户会交换租户角色，整个过程数据不丢失，RPO = 0，执行时间一般为秒级。 - Failover Failover 操作通常是在主租户出现无法恢复的故障时所做的切换行为。执行 Failover 操作后，对应的备租户角色会变换成 PRIMARY。同时，如果对主租户故障前一直正常同步的备租户执行 Failover 操作，则执行 Failover 操作后，一般会产生百毫秒级别的数据损失，执行时间一般为秒级。 - Decouple Decouple 操作是在用户计划内对租户角色进行变更，执行 Decouple 操作后，对应的备租户会和主租户解耦，备租户角色会变换为 PRIMARY。 ## Switchover 执行 Switchover 操作后，为保证拓扑关系不变，原主租户下的其他备租户切换到新主租户下，新主租户下的其他备租户切换到新备租户下，即仅交换 Switchover 操作的两个主备节点，其他节点的位置保持不变，如下图所示。 ![Switchover](https://obbusiness-private.oss-cn-shanghai.aliyuncs.com/doc/img/obd/V2.3.0/zh-CN/400.user-guide/200.role-switching-01.png) ### 前提条件 - OceanBase 数据库需为 V4.2.0.0 及以上版本。 - 主备租户所在的集群均为在线状态，可执行 `obd cluster display` 命令查看集群状态。 - 主备租户的状态均为 `NORMAL`，且备租户的日志传输状态（`sync_status`）为 `NORMAL`。可执行 `obd cluster tenant show` 命令查看。 - 主租户的租户角色（`tenant_role`）需为 `PRIMARY`。 - 对基于网络同步数据的备租户进行主备切换时，要求备租户所有日志流的副本均在线。 - 对基于日志归档同步数据的备租户进行主备切换前，需要先对备租户进行备份和归档，具体操作可参见 [备份与恢复](https://www.oceanbase.com/docs/common-obd-cn-1000000003892316) 中的 **租户备份**。 ### 操作步骤 1. 执行如下命令查看备租户的主备关系 ```shell obd cluster tenant show clusterB -g ``` 输出如下： ```shell +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | tenant base info | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | tenant_name | tenant_type | compatibility_mode | primary_zone | max_cpu | min_cpu | memory_size | max_iops | min_iops | log_disk_size | iops_weight | tenant_role | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | sys | SYS | MYSQL | RANDOM | 1.0 | 1.0 | 2.0G | 9223372036854775807 | 9223372036854775807 | 2.0G | 1 | PRIMARY | | B_a | USER | MYSQL | RANDOM | 2.0 | 2.0 | 4.0G | 10000 | 10000 | 5.0G | 2 | STANDBY | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ +-----------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant standby info | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | standby_tenant_name | tenant_status | sync_status | sync_scn_timestamp | err_code | error_comment | switchover_status | switchover_epoch | log_mode | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | B_a | NORMAL | NORMAL | 2023-09-14 09:43:00.199589 | 0 | | NORMAL | 0 | NOARCHIVELOG | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ +---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant`s primary info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby_tenant_name | primary_tenant_info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | B_a | IP_LIST=10.10.10.1:2881;10.10.10.2:2881;10.10.10.3:2881,USER=standbyro@A_a,PASSWORD=******,TENANT_ID=1002,CLUSTER_ID=1694680744,COMPATIBILITY_MODE=MYSQL,IS_ENCRYPTED=false | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ query primary-standby relation ok primary-standby relation topology graph clusterA:A_a └── clusterB:B_a ``` 2. 为备租户执行 Switchover 命令 ```shell obd cluster tenant switchover clusterB B_a --tenant-root-password=****** ``` 3. 再次查看原备租户的主备关系 ``` 输出如下 ```shell +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | tenant base info | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | tenant_name | tenant_type | compatibility_mode | primary_zone | max_cpu | min_cpu | memory_size | max_iops | min_iops | log_disk_size | iops_weight | tenant_role | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | sys | SYS | MYSQL | RANDOM | 1.0 | 1.0 | 2.0G | 9223372036854775807 | 9223372036854775807 | 2.0G | 1 | PRIMARY | | B_a | USER | MYSQL | RANDOM | 2.0 | 2.0 | 4.0G | 10000 | 10000 | 5.0G | 2 | PRIMARY | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ query primary-standby relation ok clusterB:B_a └── clusterA:A_a ``` 输出中，原备租户的 tenant_role 已更新为 `PRIMARY`，且主备关系拓扑图也已更新。 ## Failover Failover 操作适用于当主租户不可用时，可以将备租户切换为主租户继续提供服务。Failover 操作只会对日志文件做修改，不会对数据文件做修改。 由于 OceanBase 数据库的每个租户均有多个日志流，而 Failover 操作需要在操作执行完成后达到数据一致的状态，故系统会选择所有日志流的同步位点中 SCN 最小的值作为 Failover 的执行位点。执行Failover 操作后，租户下的所有日志流都会统一回退到该位点。 #### 注意 在一主多备场景中，通过执行 Failover 操作将一个备租户切换为主租户后，其他的备租户无法切换到新主租户下，您需自行选择解耦或对其他备租户执行 Failover 操作生成新的主租户。 ### 前提条件 - OceanBase 数据库需为 V4.2.0.0 及以上版本 - 主租户所在集群为不可用状态 - 备租户所在的集群为在线状态，且备租户的状态（tenant_status）需为 NORMAL - 备租户所有日志流的副本均在线 ``` 输出如下： ```shell +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | tenant base info | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | tenant_name | tenant_type | compatibility_mode | primary_zone | max_cpu | min_cpu | memory_size | max_iops | min_iops | log_disk_size | iops_weight | tenant_role | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | sys | SYS | MYSQL | RANDOM | 1.0 | 1.0 | 2.0G | 9223372036854775807 | 9223372036854775807 | 2.0G | 1 | PRIMARY | | B_a | USER | MYSQL | RANDOM | 2.0 | 2.0 | 4.0G | 10000 | 10000 | 5.0G | 2 | STANDBY | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ +-----------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant standby info | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | standby_tenant_name | tenant_status | sync_status | sync_scn_timestamp | err_code | error_comment | switchover_status | switchover_epoch | log_mode | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | B_a | NORMAL | NORMAL | 2023-09-14 10:44:04.755016 | 0 | | NORMAL | 0 | NOARCHIVELOG | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ +---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant`s primary info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby_tenant_name | primary_tenant_info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | B_a | IP_LIST=10.10.10.1:2881;10.10.10.2:2881;10.10.10.3:2881,USER=standbyro@A_a,PASSWORD=******,TENANT_ID=1002,CLUSTER_ID=1694680744,COMPATIBILITY_MODE=MYSQL,IS_ENCRYPTED=false | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ query primary-standby relation ok ``` 2. 为备租户执行 failover 命令 ```shell obd cluster tenant failover clusterB B_a --tenant-root-password=****** ``` 输出如下，B_a 租户的 tenant_role 更新为 `PRIMARY`。 ``` ## 主备租户解耦 您可执行 decouple 命令将备租户解耦为一个和主租户无关的普通租户，本节介绍如何执行 decouple 命令进行主备租户解耦。 ### 前提条件 - OceanBase 数据库需为 V4.2.0.0 及以上版本 - 备租户所在的集群为在线状态，且备租户的状态（tenant_status）需为 NORMAL - 备租户所有日志流的副本均在线 ```shell obd cluster tenant show clusterC -g ``` 输出如下： ```shell +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | tenant base info | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | tenant_name | tenant_type | compatibility_mode | primary_zone | max_cpu | min_cpu | memory_size | max_iops | min_iops | log_disk_size | iops_weight | tenant_role | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | sys | SYS | MYSQL | RANDOM | 1.0 | 1.0 | 2.0G | 9223372036854775807 | 9223372036854775807 | 2.0G | 1 | PRIMARY | | C_a | USER | MYSQL | RANDOM | 2.0 | 2.0 | 4.0G | 10000 | 10000 | 5.0G | 2 | STANDBY | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ +-----------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant standby info | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | standby_tenant_name | tenant_status | sync_status | sync_scn_timestamp | err_code | error_comment | switchover_status | switchover_epoch | log_mode | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ | C_a | NORMAL | NORMAL | 2023-09-14 09:39:32.423752 | 0 | | NORMAL | 0 | NOARCHIVELOG | +---------------------+---------------+-------------+----------------------------+----------+---------------+-------------------+------------------+--------------+ +---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby tenant`s primary info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | standby_tenant_name | primary_tenant_info | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | C_a | IP_LIST=10.10.10.1:3881;10.10.10.2:3881;10.10.10.3:3881,USER=standbyro@B_a,PASSWORD=******,TENANT_ID=1002,CLUSTER_ID=1694681525,COMPATIBILITY_MODE=MYSQL,IS_ENCRYPTED=false | +---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ query primary-standby relation ok clusterA:A_a └── clusterB:B_a └── clusterC:C_a ``` 2. 为备租户执行解耦命令 ```shell obd cluster tenant decouple clusterC C_a --tenant-root-password=****** ``` 输出如下，C_a 租户的 tenant_role 变为 `PRIMARY`。 ```shell +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | tenant base info | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | tenant_name | tenant_type | compatibility_mode | primary_zone | max_cpu | min_cpu | memory_size | max_iops | min_iops | log_disk_size | iops_weight | tenant_role | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ | sys | SYS | MYSQL | RANDOM | 1.0 | 1.0 | 2.0G | 9223372036854775807 | 9223372036854775807 | 2.0G | 1 | PRIMARY | | C_a | USER | MYSQL | RANDOM | 2.0 | 2.0 | 4.0G | 10000 | 10000 | 5.0G | 2 | PRIMARY | +-------------+-------------+--------------------+--------------+---------+---------+-------------+---------------------+---------------------+---------------+-------------+-------------+ query primary-standby relation ok ``` 上一篇 下一篇 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