前提说明：本文重点描述达梦数据守护集群之间搭建dblink配置，不记录集群部署过程，
一、环境信息
两套两节点实时主备集群环境

二、配置文件说明
配置dblink是通过mal系统进行通信，在mal配置各个节点的dmmal相互之间能够通讯，对于两个集群之间，各个节点的 dmmal.ini必须完全保持一致，如下示例

#DaMeng Database Mail Configuration file
#this is comments
MAL_CHECK_INTERVAL     = 5
MAL_COMBIN_BUF_SIZE    = 0
MAL_CONN_FAIL_INTERVAL = 5
MAL_LOGIN_TIMEOUT      = 15
MAL_BUF_SIZE           = 100
MAL_SYS_BUF_SIZE       = 0
MAL_VPOOL_SIZE         = 128
MAL_COMPRESS_LEVEL     = 0
MAL_TEMP_PATH          = 

[MAL_INST1]
    MAL_INST_NAME    = DM1  #dm.ini中instance_name保持一致
    MAL_HOST         = 192.168.100.2
    MAL_PORT         = 61141
    MAL_INST_HOST    = 192.168.100.2
    MAL_INST_PORT    = 5236 #dm.ini中port_num保持一致
    MAL_DW_PORT      = 52141
    MAL_LINK_MAGIC   = 0
    MAL_INST_DW_PORT = 33141

[MAL_INST2]
    MAL_INST_NAME    = DM2
    MAL_HOST         = 192.168.100.3
    MAL_PORT         = 61142
    MAL_INST_HOST    = 192.168.100.3
    MAL_INST_PORT    = 5236
    MAL_DW_PORT      = 52141
    MAL_LINK_MAGIC   = 0
    MAL_INST_DW_PORT = 33141

[MAL_INST3]
    MAL_INST_NAME    = DM4
    MAL_HOST         = 192.168.100.4
    MAL_PORT         = 61141
    MAL_INST_HOST    = 192.168.100.4
    MAL_INST_PORT    = 5236
    MAL_DW_PORT      = 52141
    MAL_LINK_MAGIC   = 0
    MAL_INST_DW_PORT = 33141

[MAL_INST4]
    MAL_INST_NAME    = DM5
    MAL_HOST         = 192.168.100.5
    MAL_PORT         = 61142
    MAL_INST_HOST    = 192.168.100.5                                                                                                                 
    MAL_INST_PORT    = 5236                                                                                                                          
    MAL_DW_PORT      = 52141                                                                                                                         
    MAL_LINK_MAGIC   = 0                                                                                                                             
    MAL_INST_DW_PORT = 33141 
    

三、检查mal链路是否建立成功，任意库执行
select * from v$mal_link_status;
若都是connect表示建立成功

四、创建dblink
创建dblink可通过IP/mal_port端口或者实例名进行访问
IP/mal_port端口方式：
集群1主库上创建

create public link "DM" connect 'DAMENG' with "SYSDBA" identified by "******" using '192.168.100.4/61141';

实例名方式

create public link "DM" connect 'DAMENG' with "SYSDBA" identified by "******" using 'DM4';

集群1主库访问测试