Oracle 学习之RAC(九) 集群负载均衡及故障转移
查看监听，使用grid用户
11grac1：
11grac1-> lsnrctl status LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 14-AUG-2015 00:30:26 Copyright (c) 1991, 2011, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.3.0 - Production Start Date 13-AUG-2015 22:17:25 Uptime 0 days 2 hr. 13 min. 1 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/11.2.0/grid/network/admin/listener.ora Listener Log File /u01/app/grid/diag/tnslsnr/11grac1/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.10)(PORT=1521))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.20)(PORT=1521))) Services Summary... Service "+ASM" has 1 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Service "devdb" has 1 instance(s). Instance "devdb1", status READY, has 1 handler(s) for this service... Service "devdbXDB" has 1 instance(s). Instance "devdb1", status READY, has 1 handler(s) for this service... The command completed successfully
11grac2：
11grac2-> lsnrctl status LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 14-AUG-2015 00:28:31 Copyright (c) 1991, 2011, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.3.0 - Production Start Date 13-AUG-2015 22:21:38 Uptime 0 days 2 hr. 6 min. 52 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/11.2.0/grid/network/admin/listener.ora Listener Log File /u01/app/grid/diag/tnslsnr/11grac2/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.11)(PORT=1521))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.21)(PORT=1521))) Services Summary... Service "+ASM" has 1 instance(s). Instance "+ASM2", status READY, has 1 handler(s) for this service... Service "devdb" has 1 instance(s). Instance "devdb2", status READY, has 1 handler(s) for this service... Service "devdbXDB" has 1 instance(s). Instance "devdb2", status READY, has 1 handler(s) for this service... The command completed successfully
11grac3：
11grac3-> lsnrctl status LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 14-AUG-2015 00:29:21 Copyright (c) 1991, 2011, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.3.0 - Production Start Date 13-AUG-2015 22:53:28 Uptime 0 days 1 hr. 35 min. 53 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/11.2.0/grid/network/admin/listener.ora Listener Log File /u01/app/grid/diag/tnslsnr/11grac3/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.12)(PORT=1521))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.199.22)(PORT=1521))) Services Summary... Service "+ASM" has 1 instance(s). Instance "+ASM3", status READY, has 1 handler(s) for this service... Service "devdb" has 1 instance(s). Instance "devdb3", status READY, has 1 handler(s) for this service... Service "devdbXDB" has 1 instance(s). Instance "devdb3", status READY, has 1 handler(s) for this service... The command completed successfully
每台机器的监听，都监听了自己的public-ip和vip 。
没有一台是监听scanip的。
那么我们使用scanip连接数据库试试看。
查看tnsname的配置
11grac2-> cd /u01/app/oracle/product/11.2.0/db_1/network/admin/ 11grac2-> cat tnsnames.ora # tnsnames.ora.11grac2 Network Configuration File: /u01/app/oracle/product/11.2.0/db_1/network/admin/tnsnames.ora.11grac2 # Generated by Oracle configuration tools. DEVDB = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = scan-cluster)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = devdb) ) )
使用DEVDB连接字符串登录数据库
1.
11grac2-> sqlplus sys/Ora600oracle@DEVDB as sysdba SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ devdb3
2.
11grac2-> sqlplus sys/Ora600oracle@DEVDB as sysdba SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ devdb1 SQL>
3.
11grac2-> sqlplus sys/Ora600oracle@DEVDB as sysdba SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ devdb3 SQL>
4.
11grac2-> sqlplus sys/Ora600oracle@DEVDB as sysdba SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ devdb2 SQL>
可见，在11g RAC中Oracle引入了SCAN的概念。自动实现了负载均衡。你只需连接到SCAN上，SCAN再将连接转交给数据库。并实现负载均衡。
那么我们看看如何实现故障转移。及当客户端连接的实例崩溃后，该连接会自动漂移到其他实例上。
要实现故障转移，我们要做如下配置
[root@11grac2 bin]# su - oracle 11grac2-> srvctl add service -d devdb -s DEVDB_TAF -r devdb1,devdb2,devdb3 11grac2-> srvctl start service -d devdb -s DEVDB_TAF 11grac2-> srvctl modify service -d devdb -s DEVDB_TAF -q TRUE -P BASIC -e SELECT
修改tnsname.ora,添加一个连接到DEVDB_TAF的连接字符串
11grac2-> cat tnsnames.ora # tnsnames.ora.11grac2 Network Configuration File: /u01/app/oracle/product/11.2.0/db_1/network/admin/tnsnames.ora.11grac2 # Generated by Oracle configuration tools. DEVDB = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = scan-cluster)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = devdb) ) ) DEVDB_TAF = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = scan-cluster)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = devdb_taf) ) )
验证故障转移
在11grac1上使用sys登录数据库
11grac1-> sqlplus / as sysdba SQL*Plus: Release 11.2.0.3.0 Production on Fri Aug 14 01:01:54 2015 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL> select instance_name from v$instance; INSTANCE_NAME ------------------------------------------------ devdb1 SQL> grant select any table to scott; Grant succeeded. SQL>
2. 在11grac2上使用scott用户以DEVDB_TAF连接字符串登录数据库。
11grac2-> sqlplus scott/tiger@DEVDB_TAF SQL*Plus: Release 11.2.0.3.0 Production on Fri Aug 14 01:03:28 2015 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL>
3.在11grac1的sqlplus中查看scott连接的情况
SQL> select inst_id,sid from gv$session where username='SCOTT'; INST_ID SID ---------- ---------- 2 56
4. scott用户执行一个比较耗时的查询，在执行期间，将11grac2上的实例shutdown abort
SQL> select count(*) from ( 2 select * from dba_source union 3 select * from dba_source union 4 select * from dba_source union 5 select * from dba_source union 6 select * from dba_source union 7 select * from dba_source union 8 select * from dba_source union 9 select * from dba_source union 10 select * from dba_source union 11 select * from dba_source);
SQL> shutdown abort ORACLE instance shut down.
5. 我们再去11grac1上，查看第3步执行的结果
SQL> select inst_id,sid from gv$session where username='SCOTT'; INST_ID SID ---------- ---------- 1 64
scott 的连接已经从实例2转移到实例1上了。
并且第4步的查询，结果也出来了。
SQL> select count(*) from ( 2 select * from dba_source union 3 select * from dba_source union 4 select * from dba_source union 5 select * from dba_source union 6 select * from dba_source union 7 select * from dba_source union 8 select * from dba_source union 9 select * from dba_source union 10 select * from dba_source union 11 select * from dba_source); COUNT(*) ---------- 632805