Oracle11g TAF 实例测试

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TAF(Transparent Application Failover):是指在用户正常连接后，1个节点断掉时，会话不会中断，会自动连接到另外1个节点上。

TAF和failover有一定区别，failover只会在连接时，发现1个节点断掉后，会尝试另1个节点。而连接后的故障转移是TAF。

本文主要测试TAF功能，所用的环境是部署在rhel6.5上的11.2.0.4.0的RAC，客户端连接大多是通过scan+DNS的方式。部分测试是通过VIP进行连接。

一。无TAF功能测试

1. 使用集群默认service连接

在客户端如下配置时：

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = racn-cluster-scan.pera.com)(PORT =1521))

)

(CONNECT_DATA =

(SERVICE_NAME = pera)

)

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

from V$session where username ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

18 13 NONE NONE NO

连接1个会话进行查询中。。关闭该会话连接的实例后，该会话会断开。并报如下错误：

ERROR:

ORA-03113: 通信通道的文件结尾

进程 ID: 17306

会话 ID: 27 序列号: 45

或者在连接上后，关掉连接到的实例，然后再进行查询时，也会报同样的错误。

2.使用自己创建的service连接

增加service :

[oracle@racn2 ~]$srvctl add service -d pera -s peras1 -r pera1,pera2

启动该service:

[oracle@racn2 ~]$ srvctlstart service -d pera -s peras1

关于srvctl 更多的命令：

http://docs.oracle.com/cd/E11882_01/server.112/e25494/restart.htm#ADMIN12748

修改连接：

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = racn-cluster-scan.pera.com)(PORT =1521))

)

(CONNECT_DATA =

(SERVICE_NAME = peras1)

)

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session where username='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

18 23 NONE NONE NO

就在这样的情况下去连接和上面第一个无TAF测试一样，还是不会故障转移。

二。session级服务器端的TAF

修改service

[oracle@racn2 ~]$ srvctl modify service -dpera -s peras1 -P basic -e session

还是连接到上面的service :peras1

测试session是否会TAF

连接到1个会话

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera1

关闭连接到的实例：shutdown abort

立即去查询会报下面的错误：

SQL> select instance_name fromV$instance;

select instance_name from V$instance

第 1 行出现错误:

ORA-25408: 无法安全重放调用

秒等几秒后再查询：

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera2

测试select是否会TAF

在这种情况发起1个查询:select * from dba_objects,并且在查询未完成进行时，关掉相应实例，此时不会发生select的故障转移，同样会报错：

ERROR:

ORA-03113: 通信通道的文件结尾

进程 ID: 24829

会话 ID: 224 序列号: 7

而且会断开连接：

SQL> select instance_name fromV$instance;

ERROR:

ORA-03114: 未连接到 ORACLE

三。select级服务器端的TAF

将faile_overtype 修改为select

[oracle@racn2 ~]$ srvctl modify service -dpera -s peras1 -P basic -e select

同样使用这样的连接：

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = racn-cluster-scan.pera.com)(PORT =1521))

)

(CONNECT_DATA =

(SERVICE_NAME = peras1)

)

先测试session能否正常转移

SQL> select instance_name from V$instance;

INSTANCE_NAME

--------------------------------

pera1

关闭相应实例：SQL> startup abort

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera2

经测试能够完成session级别的TAF

再测试select能否TAF

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera1

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

from V$session where username ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

21 7 SELECT BASIC NO

发起查询select * from dba_objects;

关掉实例1：

查询暂停2、3秒，然后会继续

再次查询，可以看到已经发生了failover

SQL> SELECT SID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session where username='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

15 13 SELECT BASIC YES

四。客户端配置select级的TAF

客户端连接如下：

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = racn-cluster-scan.pera.com)(PORT =1521))

)

(CONNECT_DATA =

(SERVICE_NAME = pera)

(FAILOVER_MODE=(TYPE=select)(METHOD=basic))

)

此时连接的服务端不具备TAF功能

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera2

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

from V$session where username ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

200 17 SELECT BASIC NO

同上面方法一样，经测得能够完成select 的TAF（故障转移）

五。不能loadbalance下的TAF

以上测试均是在可以load balance的情况下测试的，下面测试不能LOAD balance下可否TAF

如下连接：

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(load_balance=off)

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.114.143)(PORT = 1521))

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.114.144)(PORT = 1521))

)

(CONNECT_DATA =

(SERVICE_NAME = peras1)

)

以上的连接经测试未能实现load balance，连接了5个会话，均连接到了pera1，

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

from V$session where username ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

25 19 SELECT BASIC NO

SQL> select instance_name from

2 V$instance;

INSTANCE_NAME

--------------------------------

pera1

经测试关掉实例1后连接能够正常转移

SQL> select instance_name fromV$instance;

INSTANCE_NAME

--------------------------------

pera2

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session where username='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

229 37 SELECT BASIC YES

当然，只连接1个VIP时，虽然service：peras1是具有faile over能力，但是无法实现TAF的。因为1个节点停掉，连正常的连接都无法保证。

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.114.143)(PORT = 1521))

)

(CONNECT_DATA =

(SERVICE_NAME = peras1)

)

但是会话查询到的信息却是具有faile over能力的

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session where username='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

21 3 SELECT BASIC NO

经实际测，在查询时，关掉相应实例后，会断开，而且再也连不上

SQL> conn system/oracle@vmpera

ERROR:

ORA-12514: TNS: 监听程序当前无法识别连接描述符中请求的服务

六。客户端写明fail_over=on下的TAF

客户端连接

vmpera =

(DESCRIPTION =

(ADDRESS_LIST =

(load_balance=off)

(fail_over=off)

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.114.143)(PORT = 1521))

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.114.144)(PORT = 1521))

)

(CONNECT_DATA =

(SERVICE_NAME = peras1)

)

此时连接的service 是具有TAF功能的peras1,经实际测试，此时也能顺利的进行TAF

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session whereusername ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ------------------------------------ -------------------- ------

15 13 SELECT BASIC NO

进行查询，关实例，发现查询仍在继续，发生了TAF

SQL> SELECTSID,SERIAL#,FAILOVER_TYPE,failover_method,failed_over

2 from V$session whereusername ='SYSTEM';

SID SERIAL# FAILOVER_TYPE FAILOVER_METHOD FAILED

---------- ---------- ---------------------------------------------- ------

21 77 SELECT BASIC YES

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