遇到监听问题需要检查下列几项：

1.防火墙，selinux是否关闭

2.ping。是否网络是通的，

3.tnsping。目标库是否有服务，端口是否正确

4.listener。监听是否正常，service_name是否正确

5.session是否达到上限

这是我在检查监听的时候要检查的项目，但是今天的案例中，以上都是正确的，可sqlplus就是连不上2节点，1节点确实正常的。

dbmonitor:/home/oracle>sqlplus system/password@10.174.80.11:1521/ngjkdb1

SQL*Plus: Release 11.2.0.4.0 Production on Tue Feb 6 10:33:02 2018

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

ERROR:

ORA-12537: TNS:connection closed

sqlplus连接失败

检查连接数

SQL> set lines 200 pages 200

SQL> select *

from gv$resource_limit

where resource_name in ('processes', 'sessions')

order by resource_name, inst_id;

2    3    4

INST_ID RESOURCE_NAME                  CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION   LIMIT_VALUE

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

1 processes                                       52              98       6000                 6000

2 processes                                       49              54       6000                 6000

1 sessions                                        62             106       9024                 9024

2 sessions                                        58              66       9024                 9024

session未达到上限

检查监听

[grid@xsdbd32 ~]$ lsnrctl status LISTENER

LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 06-FEB-2018 09:28:07

Copyright (c) 1991, 2013, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))

STATUS of the LISTENER

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

Alias                     LISTENER

Version                   TNSLSNR for Linux: Version 11.2.0.4.0 - Production

Start Date                05-FEB-2018 22:21:54

Uptime                    0 days 11 hr. 6 min. 13 sec

Trace Level               off

Security                  ON: Local OS Authentication

SNMP                      OFF

Listener Parameter File   /grid/app/11.2.0/grid/network/admin/listener.ora

Listener Log File         /grid/app/grid/diag/tnslsnr/xsdbd32/listener/alert/log.xml

Listening Endpoints Summary...

(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))

(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=10.174.80.11)(PORT=1521)))

(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=10.174.80.159)(PORT=1521)))

Services Summary...

Service "+ASM" has 1 instance(s).

Instance "+ASM2", status READY, has 1 handler(s) for this service...

Service "ngjkdb1" has 1 instance(s).

Instance "ngjkdb12", status READY, has 1 handler(s) for this service...

Service "ngjkdb1XDB" has 1 instance(s).

Instance "ngjkdb12", status READY, has 1 handler(s) for this service...

The command completed successfully

监听正常，service_name=ngjkdb1, 与我之前sqlplus连接写的service_name是一致的。

然后检查了防火墙和selinux，都处于关闭状态

目前还没找到原因，查看监听日志 [grid@xsdbd32 ~]$ less /grid/app/grid/diag/tnslsnr/xsdbd32/listener/trace/listener.log

19-JAN-2018 13:57:56 * service_update * +ASM2 * 0

19-JAN-2018 13:58:00 * * 12537

TNS-12537: TNS:connection closed

TNS-12560: TNS:protocol adapter error

查询了mos,这是连接请求故意断开导致，跟我们这里的监听没有关系。

那到底是什么原因呢？

最后我检查了$ORACLE_HOME/bin/oracle这个文件，这个文件的权限必须是6751

查询并对比了1节点的oracle权限，不对，使用chmod更改，结果如下  [grid@xsdbd32 bin]$ ll oracle

-rwsr-s--x. 1 grid oinstall 210174664 Jan 26 11:28 oracle

之前的权限是751不是6751，权限显示为rwsr-x--x，需要在所属组加s权限

s 在文件执行时把进程的属主或组ID置为该文件的文件属主

再次sqlplus就可以连接上了

dbmonitor:/home/oracle/enmo/lzl>sqlplus system/password@10.174.80.11/ngjkdb1

SQL*Plus: Release 11.2.0.4.0 Production on Tue Feb 6 21:31:15 2018

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

Data Mining and Real Application Testing options

SQL>

下次检查到类似的监听问题，需要检查oracle文件的权限

另外，很多情况都要检查oracle文件的权限，比如在打补丁后有集群起不来的情况，oracle的权限可能会更改，需要像上面那样赋权6751

下面是mos上的资料

Oracle Database Fails to Start with Error ORA-12547 (文档 ID 1307075.1)

ls -l$GRID_HOME/bin/oracle

-rwsr-s--x 1 gridoinstall 203974257 May 11 09:30 oracle

ls -l$ORACLE_HOME/bin/oracle

-rwsr-s--x 1oracle asmadmin 232399431 May 14 13:47 oracle