Oracle GDS为分布在全球各地或位于同一数据中心的一组复制数据库提供以下重要功能：
基于区域的负载路由
连接时负载平衡
为 Oracle 集成客户端提供运行时负载平衡建议
数据库间服务故障切换
适用于 Active Data Guard 的基于复制延迟的负载路由
适用于 Active Data Guard 的基于角色的全局服务
集中负载管理框架
上面的图片来自官方文档，可以这样理解
在两个数据中心(APAC,EMEA 这是region)，配置了2个全局数据服务池(SALES POOL，HR POOL，这是gdspool，每套业务相关的主备库用一个gds pool)，每个数据服务池里注册了很多数据库(通过add dataase/add brokerconfig注册到gdspool)，可能是RAC + DG + OGG的架构，然后在这些gdspool中创建Global Service(通过add service)，然后可以启动这些全局服务。这些相关信息(gdspool,region,database,service)存放在GDS Catalog(类似于rman的Catalog的功能)中，管理这些东西的是GSM(Global Service Manager)。其中GSM也可以做灾备。GDS中默认的region为regionora，默认的gdspool是dbpoolora。
什么是GDS Catalog?
这个有点类似于rman的catalog，主要用于存放GDS的配置信息。数据库必须是12c之后的版本什么是GSM
是Global Service Manager的缩写，即全局服务管理器，是GDS的主要组成部分。GSM的职责如下
提供客户端连接时的负载均衡
提供service级别的负载均衡、故障转移等
监控数据库实例的可用性和全局服务的可用性，并在失败的时候通知客户端
作为区域的监听，用于客户端连接global service
12c后新增了几个用户，下面这些用户用于GDS
SQL> select username,account_status from dba_users where username like '%GSM%'; USERNAME ACCOUNT_STATUS ---------------------------------------- -------------------------------- GSMCATUSER EXPIRED & LOCKED GSMADMIN_INTERNAL EXPIRED & LOCKED GSMUSER EXPIRED & LOCKED SQL>
本文通过在ohs6上安装GSM，然后创建GDS Catalog DB，增加GSM管理器，增加GDS Pool，Region，增加数据库配置信息，创建服务，启动服务，这些是基本的操作步骤，更多复杂的配置请参考官方文档，下面是配置信息。
GSM和Catalog DB信息
Active DataGuard信息
Hosts
ohs6.ohsdba.cn
GSM_HOME
ORACLE_BASE=/pgold/ordb/oracle/product
ORACLE_HOME=/pgold/ordb/oracle/product/121/gsm
ORACLE_HOME(Catalog DB)
ORACLE_SID=pgsm
Listener Port=1521
ORACLE_BASE=/pgold/ordb/oracle/product
ORACLE_HOME=/pgold/ordb/oracle/product/121/db
gdsctl config
安装GSM软件
以下操作需满足的条件
Oracle GSM已经安装好
GDS Catalog DB数据库已安装好（数据库名字pgsm，数据库监听端口1521）
创建GDS Catalog
[oracle@ohs6 bin]$ pwd /usr/local/bin [oracle@ohs6 bin]$ [oracle@ohs6 bin]$ cat db export ORACLE_HOME=/pgold/ordb/oracle/product/121/db export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch:$PATH export ORACLE_SID=pgsm [oracle@ohs6 bin]$ cat gsm export ORACLE_HOME=/pgold/ordb/oracle/product/121/gsm export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch:$PATH [oracle@ohs6 bin]$ [root@ohs6 ~]# su - oracle [oracle@ohs6 ~]$ . db [oracle@ohs6 ~]$ sqlplus / as sysdba SQL*Plus: Release 12.1.0.2.0 Production on Fri Jan 13 11:21:07 2017 Copyright (c) 1982, 2014, Oracle. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options SQL> create user mygsm identified by mygsm default tablespace users; User created. SQL> grant gsmadmin_role to mygsm; Grant succeeded. SQL> SQL> alter user gsmcatuser identified by gsmcatuser account unlock; [oracle@ohs6 ~]$ . gsm [oracle@ohs6 ~]$ gdsctl GDSCTL: Version 12.1.0.2.0 - Production on Fri Jan 13 11:22:30 EST 2017 Copyright (c) 2011, 2014, Oracle. All rights reserved. Welcome to GDSCTL, type "help" for information. Current GSM is set to GSMORA GDSCTL>connect mygsm/mygsm@ohs6.ohsdba.cn:1521/pgsm Catalog connection is established GDSCTL>exit [oracle@ohs6 ~]$ gdsctl GDSCTL: Version 12.1.0.2.0 - Production on Fri Jan 13 11:23:34 EST 2017 Copyright (c) 2011, 2014, Oracle. All rights reserved. Welcome to GDSCTL, type "help" for information. Current GSM is set to GSMORA GDSCTL>create catalog -database ohs6.ohsdba.cn:1521/pgsm -user mygsm/mygsm Catalog is created GDSCTL>为GDS Catalog增加一个GSM
GDSCTL>add gsm -gsm gsmohs -listener 12000 -catalog ohs6.ohsdba.cn:1521/pgsm
"gsmcatuser" password:
Create credential oracle.security.client.connect_string1
GSM successfully added
GDSCTL>set gsm -gsm gsmohs
GDSCTL>
GDSCTL>config gsm -gsm gsmohs
Name: gsmohs
Endpoint 1: (ADDRESS=(HOST=ohs6.ohsdba.cn)(PORT=12000)(PROTOCOL=tcp))
Local ONS port: 6123
Remote ONS port: 6234
ORACLE_HOME path: /pgold/ordb/oracle/product/121/gsm
GSM Host name: ohs6.ohsdba.cn
Region: regionora
Buddy
------------------------
GDSCTL>start gsm -gsm gsmohs
GSM is started successfully
GDSCTL>status gsm
Alias GSMOHS
Version 12.1.0.2.0
Start Date 13-JAN-2017 11:26:26
Trace Level off
Listener Log File /pgold/ordb/oracle/product/diag/gsm/ohs6/gsmohs/alert/log.xml
Listener Trace File /pgold/ordb/oracle/product/diag/gsm/ohs6/gsmohs/trace/ora_30347_140206217676224.trc
Endpoint summary (ADDRESS=(HOST=ohs6.ohsdba.cn)(PORT=12000)(PROTOCOL=tcp))
GSMOCI Version 0.1.11
Mastership Y
Connected to GDS catalog Y
Process Id 30349
Number of reconnections 0
Pending tasks. Total 0
Tasks in process. Total 0
Regional Mastership TRUE
Total messages published 0
Time Zone -05:00
Orphaned Buddy Regions:
None
GDS region regionora
GDSCTL>
增加GDS Pool，regionGDSCTL>add gdspool -gdspool sales GDSCTL>add region -region apac,emea GDSCTL>config region Name Buddy ---- ----- regionora apac emea GDSCTL>modify region -region apac -buddy emea GDSCTL>modify region -region emea -buddy apac GDSCTL>config region Name Buddy ---- ----- regionora apac emea emea apac GDSCTL>增加database/brokerconfig到gdspool
在主库上unlock数据库用户gsmuser
SQL> alter user gsmuser identified by gsmuser account unlock;
User altered.
SQL> select username,account_status from dba_users where username like '%GSM%';
USERNAME ACCOUNT_STATUS
---------------------------------------- --------------------------------
GSMCATUSER EXPIRED & LOCKED
GSMADMIN_INTERNAL EXPIRED & LOCKED
GSMUSER OPEN
SQL> conn sys/oracle@stdby as sysdba
Connected.
SQL> select instance_name,instance_role from gv$instance;
INSTANCE_NAME INSTANCE_ROLE
---------------- ------------------
stdby2 PRIMARY_INSTANCE
stdby1 PRIMARY_INSTANCE
SQL> select username,account_status from dba_users where username like '%GSM%';
USERNAME ACCOUNT_STATUS
---------------------------------------- --------------------------------
GSMUSER OPEN
GSMADMIN_INTERNAL EXPIRED & LOCKED
GSMCATUSER EXPIRED & LOCKED
SQL> select open_mode from gv$database;
OPEN_MODE
--------------------
READ ONLY WITH APPLY
READ ONLY WITH APPLY
SQL>
完成以上步骤，然后添加数据库
GDSCTL>add brokerconfig -connect prod-scan:10010/prod -region apac -gdspool sales
"gsmuser" password:
DB Unique Name: prod
GDSCTL>config database
Name Pool Status Region
---- ---- ------ ------
prod sales Ok apac
stdby sales Ok
GDSCTL>modify database -database stdby -region emea -gdspool sales
GDSCTL>config database
Name Pool Status Region
---- ---- ------ ------
prod sales Ok apac
stdby sales Ok emea
GDSCTL>status database
Database: "prod" Registered: Y State: Ok ONS: Y. Role: PRIMARY Instances: 2 Region: apac
Registered instances:
sales%1
sales%2
Database: "stdby" Registered: Y State: Ok ONS: Y. Role: PH_STNDBY Instances: 2 Region: emea
Registered instances:
sales%11
sales%12
GDSCTL>
注意：如果配置了DG Broker，可以通过add brokerconfig添加数据库，如果没有，可以通过add database添加
为gdspoo创建服务，并启动服务
GDSCTL>add service -service prod_srv -gdspool sales -preferred_all -role PRIMARY GDSCTL> GDSCTL>config service Name Network name Pool Started Preferred all ---- ------- ---- ---- ------- --------- --- prod_srv prod_srv.sales.oradbcloud sales No Yes GDSCTL> GDSCTL>start service -service prod_srv -gdspool sales配置客户端连接字符串
prod_srv =
(DESCRIPTION=
(FAILOVER=on)
(ADDRESS_LIST=
(LOAD_BALANCE=ON)
(ADDRESS=(PROTOCOL = TCP)(host=ohs6.ohsdba.cn)(port=12000)))
(CONNECT_DATA=
(SERVICE_NAME=prod_srv.sales.oradbcloud)
(REGION=apac)
)
)
注意：这里的host为GSM服务器的信息，port为GSM的端口，service_name的格式为：服务名.gdspool名称.oradbcloud(这个是默认的)。然后通过这个TNS信息就可以连接数据库了。
Bug：GDSCTL ADD SERVICE Fails w/ NET-40063 and PRKH-1014 When Grid Infrastructure Setup is Role Separated (Doc ID 2009820.1)
GDSCTL>add service -service prod_srv -role primary -preferred_all -gdspool sales GSM Errors: NET-40063: Failed to create global service. Transaction rollbacked prod:ORA-45540: Call to SRVCTL failed with status 1, errors: PRCD-1288 : User is not authorized to create service prodsrv for database prod PRKH-1014 : Current user "orgrid" is not the oracle owner user "oracle" of oracle home "/pgold/ordb/oracle/product/121" . ORA-06512: at "GSMADMIN_INTERNAL.DBMS_GSM_DBADMIN", line 1371 ORA-06512: at line 1 (ngsmoci_execute) stdby:ORA-45540: Call to SRVCTL failed with status 1, errors: PRCD-1288 : User is not authorized to create service prodsrv for database stdby PRKH-1014 : Current user "orgrid" is not the oracle owner user "oracle" of oracle home "/pgold/ordb/oracle/product/121" . ORA-06512: at "GSMADMIN_INTERNAL.DBMS_GSM_DBADMIN", line 1371 ORA-06512: at line 1 (ngsmoci_execute) GDSCTL>注意：这个bug的意思就是说，安装RAC时，用了oracle，grid两个用户，才出现这样的情况。
http://docs.oracle.com/database/121/GSMUG/intro.htm#GSMUG108
http://docs.oracle.com/database/121/GSMUG/toc.htm
http://www.oracle.com/technetwork/cn/database/features/availability/global-data-services-1949717-zhs.html
http://www.oracle.com/technetwork/database/features/availability/demo-7-gds-2120625.html
http://www.oracle.com/technetwork/database/availability/global-data-services-12c-wp-1964780.pdf
