之前在自己的測试环境上做了个异机恢复，原来的库上是配置过EM的，可是在恢复的库上去启动EM就报错了。以下看详细解决过程：
PS：原主机名为zlm，恢复出来的主机名为bak

[root@bak ~]# su - oracle
[oracle@bak ~]$ emctl status dbconsole
TZ set to PRC
OC4J Configuration issue. /u01/app/oracle/product/10.2.0/db_1/oc4j/j2ee/OC4J_DBConsole_bak_ora10g not found. 
[oracle@bak ~]$ cd /u01/app/oracle/product/10.2.0/db_1/oc4j/j2ee/
[oracle@bak j2ee]$ ll
total 24
-rw-r--r--  1 oracle oinstall  256 Aug 22 16:42 deploy_db.ini
drwxr-x--- 15 oracle oinstall 4096 Aug 22 16:29 home
drwxr-x---  9 oracle oinstall 4096 Aug 22 16:24 isqlplus
drwxr-x---  3 oracle oinstall 4096 Aug 22 16:24 oc4j_applications
drwxr-x---  5 oracle oinstall 4096 Aug 22 16:24 OC4J_DBConsole
drwxr-x---  7 oracle oinstall 4096 Aug 25 11:25 OC4J_DBConsole_zlm_ora10g

既然提示文件找不到。非常显然是由于主机名变更的缘故，那么把名字变一下，用mv命令

[oracle@bak j2ee]$ mv -r OC4J_DBConsole_zlm_ora10g/ OC4J_DBConsole_bak_ora10g/
[oracle@bak j2ee]$ ll
total 24
-rw-r--r--  1 oracle oinstall  256 Aug 22 16:42 deploy_db.ini
drwxr-x--- 15 oracle oinstall 4096 Aug 22 16:29 home
drwxr-x---  9 oracle oinstall 4096 Aug 22 16:24 isqlplus
drwxr-x---  3 oracle oinstall 4096 Aug 22 16:24 oc4j_applications
drwxr-x---  5 oracle oinstall 4096 Aug 22 16:24 OC4J_DBConsole
drwxr-x---  7 oracle oinstall 4096 Oct 20 10:58 OC4J_DBConsole_bak_ora10g
[oracle@bak j2ee]$ emctl status dbconsole
TZ set to PRC
EM Configuration issue. /u01/app/oracle/product/10.2.0/db_1/bak_ora10g not found. 
[oracle@bak j2ee]$ cd /u01/app/oracle/product/10.2.0/db_1/
[oracle@bak db_1]$ ll
total 260
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:24 assistants
drwxr-xr-x  2 oracle oinstall 12288 Aug 22 16:42 bin
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:33 cdata
drwxr-x---  6 oracle oinstall  4096 Aug 25 11:08 cfgtoollogs
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:24 clone
drwxr-x---  2 oracle oinstall  4096 Aug 22 16:33 config
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:24 crs
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:33 css
drwxr-x--- 10 oracle oinstall  4096 Aug 22 16:33 ctx
drwxr-x---  2 oracle oinstall  4096 Oct 20 09:17 dbs
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 demo
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 diagnostics
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 has
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:42 hs
drwxr-x---  5 oracle oinstall  4096 Aug 25 11:27 install
-rw-r-----  1 oracle oinstall    37 Aug 22 16:24 install.platform
drwxr-x--- 12 oracle oinstall  4096 Aug 22 16:42 inventory
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:24 javavm
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:31 jdbc
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:32 jdk
drwxr-x---  2 oracle oinstall  4096 Aug 22 16:32 jlib
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 jre
drwxr-x--- 13 oracle oinstall  4096 Aug 22 16:33 ldap
drwxr-x---  3 oracle oinstall 12288 Aug 22 16:42 lib
drwxr-x--T  3 oracle oinstall  4096 Aug 25 11:24 log
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:24 md
drwxr-x---  2 oracle oinstall  4096 Aug 22 16:25 mesg
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:32 mgw
drwxr-x--- 11 oracle oinstall  4096 Aug 22 16:42 network
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:24 nls
drwxr-x--- 15 oracle oinstall  4096 Aug 22 16:42 oc4j
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:24 odbc
drwxr-x---  5 oracle oinstall  4096 Aug 22 16:24 olap
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:32 OPatch
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:32 opmn
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:24 oracore
-rw-r--r--  1 oracle oinstall    63 Aug 22 16:22 oraInst.loc
drwxr-x---  8 oracle oinstall  4096 Aug 22 16:24 ord
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:32 oui
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:24 owm
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:24 perl
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:25 plsql
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:24 precomp
drwxr-x---  7 oracle oinstall  4096 Aug 22 16:33 racg
drwxr-x--- 13 oracle oinstall  4096 Aug 22 16:42 rdbms
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:31 relnotes
-rwxr-xr-x  1 oracle oinstall  9522 Aug 22 16:42 root.sh
-rwxr-xr-x  1 oracle oinstall     0 Jun  7  2005 root.sh.old
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 slax
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 sqlj
-rw-r-----  1 oracle oinstall  9338 Aug 25 11:42 sqlnet.log
drwxr-x---  9 oracle oinstall  4096 Aug 22 16:33 sqlplus
drwxr-x--- 12 oracle oinstall  4096 Aug 22 16:33 srvm
drwxr-x--- 12 oracle oinstall  4096 Aug 22 16:33 sysman
drwxr-x---  4 oracle oinstall  4096 Aug 22 16:24 uix
drwxr-x---  3 oracle oinstall  4096 Aug 22 16:24 wwg
drwxr-x---  6 oracle oinstall  4096 Aug 22 16:30 xdk
drwxr-----  3 oracle oinstall  4096 Aug 25 11:25 zlm_ora10g

这次是找不到zlm_ora10g文件夹，相同的，也mv为bak_ora10g

[oracle@bak db_1]$ mv zlm_ora10g bak_ora10g
[oracle@bak db_1]$ emctl status dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://zlm:1158/em/console/aboutApplication
Oracle Enterprise Manager 10g is not running. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log 
[oracle@bak j2ee]$ emctl start dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://zlm:1158/em/console/aboutApplication
Starting Oracle Enterprise Manager 10g Database Control .................................. started. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log 

无法启动，看到url里的信息是原主机zlm，分析一下提示的错误日志

[oracle@bak j2ee]$ cd /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log
[oracle@bak log]$ ll
total 1656
-rw-r----- 1 oracle oinstall    180 Aug 25 11:28 emagentfetchlet.log
-rw-r----- 1 oracle oinstall    180 Aug 25 11:28 emagentfetchlet.trc
-rw-r----- 1 oracle oinstall    500 Oct 20 11:06 emagent.log
-rw-r----- 1 oracle oinstall  42010 Oct 20 11:14 emagent.trc
-rw-r----- 1 oracle oinstall   9816 Oct 20 11:05 emdb.nohup
-rw-r----- 1 oracle oinstall   4096 Oct 20 11:05 emdb.nohup.lr
-rw-r----- 1 oracle oinstall      0 Aug 25 11:25 emdctl.log
-rw-r----- 1 oracle oinstall   7330 Oct 20 11:14 emdctl.trc
-rw-r----- 1 oracle oinstall 802261 Aug 25 11:45 emoms.log
-rw-r----- 1 oracle oinstall 802261 Aug 25 11:45 emoms.trc
[oracle@bak log]$ cat emoms.log
2014-08-25 11:26:23,952 [Orion Launcher] WARN  jdbc.ConnectionCache _getConnection.303 - Got a fatal exeption when getting a connection; Error code = 17002; Cleaning up cache and retrying
2014-08-25 11:26:23,991 [Orion Launcher] WARN  jdbc.ConnectionCache _getConnection.306 - Io exception: The Network Adapter could not establish the connection
java.sql.SQLException: Io exception: The Network Adapter could not establish the connection
        at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:111)
        at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:145)
        at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:254)
        at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:386)
        at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:493)
        at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:164)
        at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:34)
        at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:767)
        at oracle.jdbc.pool.OracleDataSource.getPhysicalConnection(OracleDataSource.java:324)
        at oracle.jdbc.pool.OracleConnectionPoolDataSource.getPooledConnection(OracleConnectionPoolDataSource.java:114)
        at oracle.jdbc.pool.OracleConnectionCacheImpl.getNewPoolOrXAConnection(OracleConnectionCacheImpl.java:694)
        at oracle.jdbc.pool.OracleConnectionCacheImpl.getPooledConnection(OracleConnectionCacheImpl.java:540)
        at oracle.jdbc.pool.OracleConnectionCacheImpl.getConnection(OracleConnectionCacheImpl.java:346)
        at oracle.jdbc.pool.OracleConnectionCacheImpl.getConnection(OracleConnectionCacheImpl.java:324)
        at oracle.sysman.util.jdbc.ConnectionCache._getConnection(ConnectionCache.java:296)
        at oracle.sysman.util.jdbc.ConnectionCache.getUnwrappedConnection(ConnectionCache.java:423)
        at oracle.sysman.emSDK.svc.conn.FGAConnectionCache.getFGAConnection(FGAConnectionCache.java:156)
        at oracle.sysman.emSDK.svc.conn.ConnectionService.getPrivateConnection(ConnectionService.java:605)
        at oracle.sysman.emSDK.svc.conn.ConnectionService.getRepositoryVersionAndMode(ConnectionService.java:368)
        at oracle.sysman.emSDK.svc.conn.ConnectionService.verifyRepositoryEx(ConnectionService.java:395)
        at oracle.sysman.emSDK.svc.conn.ConnectionService.verifyRepository(ConnectionService.java:450)
        at oracle.sysman.eml.app.ContextInitializer.contextInitialized(ContextInitializer.java:174)
        at com.evermind.server.http.HttpApplication.initDynamic(HttpApplication.java:807)
        at com.evermind.server.http.HttpApplication.<init>(HttpApplication.java:533)
        at com.evermind.server.Application.getHttpApplication(Application.java:886)
        at com.evermind.server.http.HttpServer.getHttpApplication(HttpServer.java:688)
        at com.evermind.server.http.HttpSite.initApplications(HttpSite.java:570)
        at com.evermind.server.http.HttpSite.setConfig(HttpSite.java:263)
        at com.evermind.server.http.HttpServer.setSites(HttpServer.java:259)
        at com.evermind.server.http.HttpServer.setConfig(HttpServer.java:160)
        at com.evermind.server.ApplicationServer.initializeHttp(ApplicationServer.java:2330)
        at com.evermind.server.ApplicationServer.setConfig(ApplicationServer.java:1503)
        at com.evermind.server.ApplicationServerLauncher.run(ApplicationServerLauncher.java:93)
        at java.lang.Thread.run(Thread.java:534)
2014-08-25 11:26:23,999 [Orion Launcher] ERROR conn.ConnectionService verifyRepositoryEx.433 - Invalid Connection Pool. ERROR = Io exception: The Network Adapter could not establish the connection
2014-08-25 11:26:26,673 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ias.ias.IASIntegration
2014-08-25 11:26:27,386 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.eml.target.slb.common.SLBIntegration
2014-08-25 11:26:27,676 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.eml.ssl.intg.SSLIntegration
2014-08-25 11:26:27,915 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.tip.oem.central.domain.ProcessConnectDomainIntg
2014-08-25 11:26:27,918 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.tip.oem.central.instance.ProcessConnectInstanceIntg
2014-08-25 11:26:27,932 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.webdb.admin.em.PortalIntegration
2014-08-25 11:26:27,934 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.webdb.admin.em.SSOIntegration
2014-08-25 11:26:27,937 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.reports.em.RepIntg
2014-08-25 11:26:27,940 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsEmailIntegration
2014-08-25 11:26:27,945 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsOidIntegration
2014-08-25 11:26:27,948 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsOvfIntegration
2014-08-25 11:26:27,970 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsWebconfIntegration
2014-08-25 11:26:27,975 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsWirelessIntg
2014-08-25 11:26:27,978 [Orion Launcher] ERROR app.ContextInitializer contextInitialized.271 - Integration Class not found: oracle.sysman.ocs.mntr.target.OcsCalGrpIntegration

刷屏了。中间省略同样错误一堆，按Ctrl+C才终止的

2014-08-25 11:29:24,713 [HttpRequestHandler-23603795] ERROR conn.ConnectionService verifyRepositoryEx.433 - Invalid Connection Pool. ERROR = Io exception: The Network Adapt

怀疑是否是由于监听没起来的缘故，先启动监听

[oracle@bak log]$ lsnrctl status

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 20-OCT-2014 11:15:26

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   Linux Error: 111: Connection refused
[oracle@bak log]$ lsnrctl start

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 20-OCT-2014 11:15:29

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/10.2.0/db_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Log messages written to /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=bak)(PORT=1521)))

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date                20-OCT-2014 11:15:29
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=bak)(PORT=1521)))
The listener supports no services
The command completed successfully
[oracle@bak log]$ lsnrctl status

LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 20-OCT-2014 11:16:17

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Start Date                20-OCT-2014 11:15:29
Uptime                    0 days 0 hr. 0 min. 48 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=bak)(PORT=1521)))
Services Summary...
Service "ora10g" has 1 instance(s).
  Instance "ora10g", status READY, has 1 handler(s) for this service...
Service "ora10gXDB" has 1 instance(s).
  Instance "ora10g", status READY, has 1 handler(s) for this service...
Service "ora10g_XPT" has 1 instance(s).
  Instance "ora10g", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@bak log]$ emctl status dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://zlm:1158/em/console/aboutApplication
Oracle Enterprise Manager 10g is not running. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log 

显然，EM启动不了不是监听的问题。那么又一次配置一下EM是否会有效呢？

[oracle@bak log]$ emca -config dbcontrol db

STARTED EMCA at Oct 20, 2014 11:22:43 AM
EM Configuration Assistant, Version 10.2.0.1.0 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.

Enter the following information:    --注意，此处信息须要手动输入
Database SID: ora10g
Database Control is already configured for the database ora10g
You have chosen to configure Database Control for managing the database ora10g
This will remove the existing configuration and the default settings and perform a fresh configuration
Do you wish to continue? [yes(Y)/no(N)]: y
Listener port number: 1521
Password for SYS user:  
Password for DBSNMP user:  
Password for SYSMAN user:  
Password for SYSMAN user: oEmail address for notifications (optional):      
Invalid email.
Email address for notifications (optional): 
Outgoing Mail (SMTP) server for notifications (optional): 
-----------------------------------------------------------------

You have specified the following settings

Database ORACLE_HOME ................ /u01/app/oracle/product/10.2.0/db_1

Database hostname ................ bak
Listener port number ................ 1521
Database SID ................ ora10g
Email address for notifications ............... 
Outgoing Mail (SMTP) server for notifications ............... 

-----------------------------------------------------------------
Do you wish to continue? [yes(Y)/no(N)]: y
Oct 20, 2014 11:24:36 AM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /u01/app/oracle/product/10.2.0/db_1/cfgtoollogs/emca/ora10g/emca_2014-10-20_11-22-43-AM.log.
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
Oct 20, 2014 11:25:53 AM oracle.sysman.emcp.ParamsManager getLocalListener
WARNING: Error retrieving listener for bak
Oct 20, 2014 11:26:15 AM oracle.sysman.emcp.EMConfig perform
SEVERE: Cannot start Database Control. The following ports are already in use: [EM agent port:3938].
Refer to the log file at /u01/app/oracle/product/10.2.0/db_1/cfgtoollogs/emca/ora10g/emca_2014-10-20_11-22-43-AM.log for more details.
Could not complete the configuration. Refer to the log file at /u01/app/oracle/product/10.2.0/db_1/cfgtoollogs/emca/ora10g/emca_2014-10-20_11-22-43-AM.log for more details.
[oracle@bak log]$ cat /u01/app/oracle/product/10.2.0/db_1/cfgtoollogs/emca/ora10g/emca_2014-10-20_11-22-43-AM.log

发现也是一堆报错，当中有一段是这种，显示地主机命名还是之前旧的信息（原来的主机名为zlm，如今的为bak）：

CONFIG: emdProps: /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/config/emd.properties url: http://zlm:1158/em
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.EMDBPreConfig isDBControlSecure
CONFIG:  isDbcSecure: false
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.ParamsManager setFlag
CONFIG: Flag 'IS_DBCONSOLE_SECURED' set to false
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.util.PlatformInterface getSortedEnvArray
CONFIG: New Env List: [DISPLAY=, NEED_EXIT_CODE=1, ORACLE_SID=ora10g, PATH=/usr/sbin:/u01/app/oracle/product/10.2.0/db_1/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/mysql/bin:/usr/local/mysql/bin:/home/oracle/bin, TZ=]
Oct 20, 2014 11:24:49 AM oracle.sysman.emcp.util.PlatformInterface executeCommand
CONFIG: Starting execution: /u01/app/oracle/product/10.2.0/db_1/bin/emctl stop dbconsole 
Oct 20, 2014 11:25:43 AM oracle.sysman.emcp.util.PlatformInterface executeCommand
CONFIG: Exit value of 0
Oct 20, 2014 11:25:43 AM oracle.sysman.emcp.util.PlatformInterface executeCommand
CONFIG: Execution of /u01/app/oracle/product/10.2.0/db_1/bin/emctl stop dbconsole  completed successfully
Oct 20, 2014 11:25:43 AM oracle.sysman.emcp.util.PlatformInterface executeCommand
CONFIG: TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://zlm:1158/em/console/aboutApplication
Stopping Oracle Enterprise Manager 10g Database Control ... 
 ...  Stopped. 

看来只又一次配置一下EM资料库是不行的，须要重建一下（先删除，后创建）

[oracle@bak log]$ emca -repos recreate 
shell-init: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory
Error occurred during initialization of VM
java.lang.Error: Properties init: Could not determine current working directory.

该错误表示 getcwd 命令无法定位到当前工作文件夹。一般来说是由于 cd 到了某个文件夹之后又rm 了这个文件夹
这时去运行某些命令就会报 getcwd 错误​，仅仅须要 cd 到不论什么一个实际存在的文件夹下在运行命令就可以。
出现这样的现象的原因还有，当前用户没有当前文件夹的可运行权限。如没有正确设置ORACLE_SID环境变量。我这里属于这样的情况。


[oracle@bak log]$ set ORACLE_SID=ora10g
[oracle@bak log]$ emca -repos recreate

STARTED EMCA at Oct 20, 2014 11:49:36 AM
EM Configuration Assistant, Version 10.2.0.1.0 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.

Enter the following information:
Database SID: ora10g
Listener port number: 1521
Password for SYS user:  
Password for SYSMAN user:  
Password for SYSMAN user:  
Do you wish to continue? [yes(Y)/no(N)]: y
Oct 20, 2014 11:49:59 AM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /u01/app/oracle/product/10.2.0/db_1/cfgtoollogs/emca/ora10g/emca_2014-10-20_11-49-36-AM.log.
Oct 20, 2014 11:50:01 AM oracle.sysman.emcp.EMReposConfig dropRepository    --删除
INFO: Dropping the EM repository (this may take a while) ...
Oct 20, 2014 11:54:25 AM oracle.sysman.emcp.EMReposConfig invoke
INFO: Repository successfully dropped
Oct 20, 2014 11:54:25 AM oracle.sysman.emcp.EMReposConfig createRepository    --创建
INFO: Creating the EM repository (this may take a while) ...
Oct 20, 2014 11:59:58 AM oracle.sysman.emcp.EMReposConfig invoke
INFO: Repository successfully created
Enterprise Manager configuration completed successfully
FINISHED EMCA at Oct 20, 2014 11:59:58 AM

能够看到3个successfully，重建后并把em配置也又一次刷了一遍

[oracle@bak log]$ emctl status dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://bak:1158/em/console/aboutApplication    --重建EM资料库后。如今的主机名已经更正为“bak”了
Oracle Enterprise Manager 10g is not running.

再次又一次启动EM

[oracle@bak log]$ emctl start dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://bak:1158/em/console/aboutApplication
Agent Version     : 10.1.0.4.1
OMS Version       : Unknown
Protocol Version  : 10.1.0.2.0
Agent Home        : /u01/app/oracle/product/10.2.0/db_1/bak_ora10g
Agent binaries    : /u01/app/oracle/product/10.2.0/db_1
Agent Process ID  : 29136
Parent Process ID : 28566
Agent URL         : http://zlm:3938/emd/main    --agent还是有原主机残留信息，没有更新。只是不影响登陆EM
Started at        : 2014-10-20 11:05:11
Started by user   : oracle
Last Reload       : 2014-10-20 11:05:11
Last successful upload                       : (none)
Last attempted upload                        : (none)
Total Megabytes of XML files uploaded so far :     0.00
Number of XML files pending upload           :       40
Size of XML files pending upload(MB)         :     5.84
Available disk space on upload filesystem    :     5.14%
Agent is already started. Will restart the agent 
Stopping agent ... stopped.
Starting Oracle Enterprise Manager 10g Database Control ........ started. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log 
[oracle@bak log]$ emctl status dbconsole
TZ set to PRC
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0  
Copyright (c) 1996, 2005 Oracle Corporation.  All rights reserved.
http://bak:1158/em/console/aboutApplication
Oracle Enterprise Manager 10g is running. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/10.2.0/db_1/bak_ora10g/sysman/log 
[oracle@bak log]$ 

通过重建EM后，就能够用web浏览器登陆EM管理界面了，新的url为：http://bak:1158/em

总结：

遇到各种原因造成的EM无法登陆的问题，一般是由于旧的EM资料库配置有问题，或者是由于改变了主机或IP地址所造成，能够使用emca -repos recreate重建，就能直接解决这个问题，只通过emca -config dbconsole db来又一次配置是不够彻底的，由于还会有之前错误信息的残留，除了这几个命令外，emca还有非常多其它參数。能够通过emca --help查看，这里就不列举了。