AntDB 数据库分布式运维手册-集群节点管理7

非故障切换

当用户需要将原主机切换被备机，原备机切换为主机，可以使用 switchover 命令：

antdb=# SWITCHOR DATANODE SLAVE dn2_2; 
NOTICE:  wait max 10 seconds to wait there are no active connections on coordinators and master nodes 
NOTICE:  gcn1 try lock cluster successfully 
NOTICE:  wait max 10 seconds to check there are no active locks in pg_locks except the locks on pg_locks table 
NOTICE:  wait max 10 seconds to check dn2_1 and dn2_2 have the same xlog position 
NOTICE:  dn2_2 was successfully promoted to the new master 
NOTICE:  dn2_2 running on correct status of master mode 
NOTICE:  dn2_1 running on correct status of slave mode 
NOTICE:  gcn1 try unlock cluster successfully 
NOTICE:  Switch the datanode master from dn2_1 to dn2_2 has been successfully completed 
 nodename | status |    description     
----------+--------+------------------- 
 dn2_2    | t      | promotion success 
(1 row) 
 
antdb=# list node dn2_2; 
 name  | host  |      type       | mastername | port  | sync_state |               path               | initialized | incluster | readonly | zone   
-------+-------+-----------------+------------+-------+------------+----------------------------------+-------------+-----------+----------+------- 
 dn2_2 | adb01 | datanode master |            | 52542 |            | /data/antdb/data/adb50/d2/dn2_2 | t           | t         | f        | local 
(1 row) 
 
antdb=# list node dn2_1; 
 name  | host  |      type      | mastername | port  | sync_state |               path               | initialized | incluster | readonly | zone   
-------+-------+----------------+------------+-------+------------+----------------------------------+-------------+-----------+----------+------- 
 dn2_1 | adb01 | datanode slave | dn2_2      | 52541 | sync       | /data/antdb/data/adb50/d1/dn2_1 | t           | t         | f        | local 
(1 row) 

可以看到，主备之间发生了切换。