达梦数据库主从切换(takeover)

环境:
OS:Centos 7
DB:V8

1.手工执行监控器

[dmdba@host02 DAMENG]$ dmmonitor /dmdbms/data/DAMENG/dmmonitor.ini
login
username:sysdba
password:
[monitor]         2024-03-25 09:54:55: Login dmmonitor success!

choose takeover GRP1
Group(grp1) has active primary instance, not get standby instance list any more!

我这里主从目前是正常的,所以takeover不能使用

2.查看当前主库

[dmdba@host02 DAMENG]$ dmmonitor /dmdbms/data/DAMENG/dmmonitor.ini
login
username:sysdba
password:
[monitor]         2024-03-25 09:54:55: Login dmmonitor success!
show
2024-03-25 09:56:15 
#================================================================================#
GROUP            OGUID       MON_CONFIRM     MODE            MPP_FLAG  
GRP1             453332      TRUE            AUTO            FALSE     


<<DATABASE GLOBAL INFO:>>
DW_IP          MAL_DW_PORT  WTIME                WTYPE     WCTLSTAT  WSTATUS        INAME            INST_OK   N_EP  N_OK  ISTATUS     IMODE     DSC_STATUS     RTYPE     RSTAT    
192.168.1.101  52141        2024-03-25 09:56:14  GLOBAL    VALID     OPEN           DAMENG           OK        1     1     OPEN        PRIMARY   DSC_OPEN       REALTIME  VALID    

EP INFO:
INST_IP        INST_PORT  INST_OK   INAME            ISTATUS     IMODE     DSC_SEQNO  DSC_CTL_NODE RTYPE     RSTAT       FSEQ            FLSN            CSEQ            CLSN            DW_STAT_FLAG          
192.168.1.101  5236       OK        DAMENG           OPEN        PRIMARY   0          0            REALTIME  VALID       5554            48915           5554            48915           NONE                  

<<DATABASE GLOBAL INFO:>>
DW_IP          MAL_DW_PORT  WTIME                WTYPE     WCTLSTAT  WSTATUS        INAME            INST_OK   N_EP  N_OK  ISTATUS     IMODE     DSC_STATUS     RTYPE     RSTAT    
192.168.1.104  52141        2024-03-25 09:56:15  GLOBAL    VALID     OPEN           DAMENGBAK        OK        1     1     OPEN        STANDBY   DSC_OPEN       REALTIME  VALID    

EP INFO:
INST_IP        INST_PORT  INST_OK   INAME            ISTATUS     IMODE     DSC_SEQNO  DSC_CTL_NODE RTYPE     RSTAT       FSEQ            FLSN            CSEQ            CLSN            DW_STAT_FLAG          
192.168.1.104  5236       OK        DAMENGBAK        OPEN        STANDBY   0          0            REALTIME  VALID       5554            48915           5554            48915           NONE                  

DATABASE(DAMENGBAK) APPLY INFO FROM (DAMENG), REDOS_PARALLEL_NUM (1), WAIT_APPLY[FALSE]:
DSC_SEQNO[0], (RSEQ, SSEQ, KSEQ)[5554, 5554, 5554], (RLSN, SLSN, KLSN)[48915, 48915, 48915], N_TSK[0], TSK_MEM_USE[0] 
REDO_LSN_ARR: (48915)

主库是192.168.1.101

3.关闭监视器服务
systemctl stop DmMonitorServiceMonitor

4.对主库进行down机
我这里直接关闭机器电源

5.查看当前从库的状态

[dmdba@host02 DAMENG]$ disql hxl/dameng123

Server[LOCALHOST:5236]:mode is standby, state is open
login used time : 3.156(ms)
disql V8
SQL> select status$,mode$ from v$instance;

LINEID     status$ mode$  
---------- ------- -------
1          OPEN    STANDBY

used time: 41.738(ms). Execute id is 501.

6.手工启动监视器进程进行切换
手工启动监视服务器的,有配置监视服务器配置文件dmmonitor.ini即可

[dmdba@host02 arch]$ dmmonitor /dmdbms/data/DAMENG/dmmonitor.ini
[monitor]         2024-03-25 10:09:26: DMMONITOR[4.0] V8
[monitor]         2024-03-25 10:09:28: DMMONITOR[4.0] IS READY.
login ##输入该命令
username:sysdba
password:
[monitor]         2024-03-25 10:10:05: Login dmmonitor success!

choose takeover GRP1 ##输入该命令
no database can do takeover!

choose switchover GRP1 ##输入该命令
no instance can do switchover!


show global info


takeover GRP1.DAMENGBAK ##输入该命令
[monitor]         2024-03-25 10:22:33: Get instance(DAMENGBAK)'s PRIMARY instance info failed(instance DAMENGBAK has not received any archive message from PRIMARY instance)

takeover force GRP1.DAMENGBAK ##输入该命令,强制接管 takeover force 组名.实例名
Be careful to do so, this operation may cause data split, please confirm to continue or not(Y/N)?

提示会出现脑裂,这种情况下的需要重新部署主从.

这个时候数据库的状态:

SQL> select status$,mode$ from v$instance;

LINEID     status$ mode$  
---------- ------- -------
1          OPEN    PRIMARY

used time: 0.638(ms). Execute id is 502.

7.启动原来的主库
原来的主库开机后查看数据库状态

[dmdba@host01 ~]$ disql hxl/dameng123

Server[LOCALHOST:5236]:mode is standby, state is open
login used time : 3.937(ms)
disql V8
SQL> select status$,mode$ from v$instance;

LINEID     status$ mode$  
---------- ------- -------
1          OPEN    STANDBY

used time: 14.153(ms). Execute id is 1