ORA-01102: cannot mount database in EXCLUSIVE mode
安装完ORACEL 10g数据库后,启动数据库时遇到ORA-01102: cannot mount database in EXCLUSIVE mode
[oracle@DB-Server ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Thu Apr 10 13:53:08 2014
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 5033164800 bytes
Fixed Size 2027672 bytes
Variable Size 905973608 bytes
Database Buffers 4110417920 bytes
Redo Buffers 14745600 bytes
ORA-01102: cannot mount database in EXCLUSIVE mode
查看告警日志文件，发现有ORA-09968: unable to lock file 和Linux-x86_64 Error: 11: Resource temporarily unavailable等错误
[oracle@DB-Server bdump]$ tail -20f alert_epps.log
SMON started with pid=8, OS id=24482
RECO started with pid=9, OS id=24484
CJQ0 started with pid=10, OS id=24486
MMON started with pid=11, OS id=24488
Thu Apr 10 13:53:42 2014
starting up 1 dispatcher(s) for network address '(ADDRESS=(PARTIAL=YES)(PROTOCOL=TCP))'...
MMNL started with pid=12, OS id=24490
Thu Apr 10 13:53:42 2014
starting up 1 shared server(s) ...
Thu Apr 10 13:53:42 2014
ALTER DATABASE MOUNT
Thu Apr 10 13:53:42 2014
sculkget: failed to lock /u01/app/oracle//product/10.2.0/db_1/dbs/lkEPPS exclusive
sculkget: lock held by PID: 20337
Thu Apr 10 13:53:42 2014
ORA-09968: unable to lock file
Linux-x86_64 Error: 11: Resource temporarily unavailable
Additional information: 20337
Thu Apr 10 13:53:42 2014
ORA-1102 signalled during: ALTER DATABASE MOUNT...
第一次遇到这种情况，于是网上搜索了一下资料，找到一篇相关文章http://blog.itpub.net/12272958/viewspace-716020，介绍了出现这种错误的三种情况：
a、 Oracle的共享内存段或信号量没有被释放；
b、 Oracle的后台进程（如SMON、PMON、DBWn等）没有被关闭；
c、 用于锁内存的文件lk<sid>和sgadef<sid>.dbf文件没有被删除。
看了文章前面一部分。便武断的觉得应该是第三者情况（由于告警日志中出现了相关信息）：“用于锁内存的文件lk<sid>和sgadef<sid>.dbf文件没有被删除”。于是动手操作（太心急，这毛病老是难以改变），关闭数据库实例，删除/u01/app/oracle/product/10.2.0/db_1/dbs/lkEPPS文件后，重新启动数据库。结果作者的经历又在我身上重演了一次。
启动时候报ORA-00205错误
SQL> shutdown immediate;
ORA-01507: database not mounted
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 5033164800 bytes
Fixed Size 2027672 bytes
Variable Size 905973608 bytes
Database Buffers 4110417920 bytes
Redo Buffers 14745600 bytes
ORA-00205: error in identifying control file, check alert log for more info
查看告警日志，有如下错误信息：
RECO started with pid=9, OS id=24887
CJQ0 started with pid=10, OS id=24889
MMON started with pid=11, OS id=24891
Thu Apr 10 14:04:05 2014
starting up 1 dispatcher(s) for network address '(ADDRESS=(PARTIAL=YES)(PROTOCOL=TCP))'...
MMNL started with pid=12, OS id=24894
Thu Apr 10 14:04:06 2014
starting up 1 shared server(s) ...
Thu Apr 10 14:04:06 2014
ALTER DATABASE MOUNT
Thu Apr 10 14:04:06 2014
ORA-00202: control file: '/u01/app/oracle/oradata/epps/control01.ctl'
ORA-27086: unable to lock file - already in use
Linux-x86_64 Error: 11: Resource temporarily unavailable
Additional information: 8
Additional information: 20341
Thu Apr 10 14:04:09 2014
ORA-205 signalled during: ALTER DATABASE MOUNT...
于是索性静下心来多了解一下这个问题，在网上查看了大量关于ORA-01102的文章。这篇博客http://blog.itpub.net/20674423/viewspace-711545对这个问题阐述得比较清晰。下面是Metalink关于ORA-01102的解释以及解决方法：
Problem Description:
====================
You are trying to startup the database and you receive the following error:
ORA-01102: cannot mount database in EXCLUSIVE mode
Cause: Some other instance has the database mounted exclusive or shared.
Action: Shutdown other instance or mount in a compatible mode.
Problem Explanation:
====================
A database is started in EXCLUSIVE mode by default. Therefore, the ORA-01102 error is misleading and may have occurred due to one of the following reasons:
- there is still an "sgadef<sid>.dbf" file in the "ORACLE_HOME/dbs" directory
- the processes for Oracle (pmon, smon, lgwr and dbwr) still exist
- shared memory segments and semaphores still exist even though the
database has been shutdown
- there is a "ORACLE_HOME/dbs/lk<sid>" file
Search Words:
=============
ORA-1102, crash, immediate, abort, fail, fails, migration
Solution Description:
=====================
Verify that the database was shutdown cleanly by doing the following:
1. Verify that there is not a "sgadef<sid>.dbf" file in the directory "ORACLE_HOME/dbs".
% ls $ORACLE_HOME/dbs/sgadef<sid>.dbf If this file does exist, remove it.
% rm $ORACLE_HOME/dbs/sgadef<sid>.dbf
2. Verify that there are no background processes owned by "oracle"
% ps -ef | grep ora_ | grep $ORACLE_SID
If background processes exist, remove them by using the Unix
command "kill". For example:
% kill -9 <rocess_ID_Number>
3. Verify that no shared memory segments and semaphores that are owned by "oracle" still exist
% ipcs -b
If there are shared memory segments and semaphores owned by "oracle", remove the shared memory segments
% ipcrm -m <Shared_Memory_ID_Number>
and remove the semaphores
% ipcrm -s <Semaphore_ID_Number>
NOTE: The example shown above assumes that you only have one
database on this machine. If you have more than one
database, you will need to shutdown all other databases
before proceeding with Step 4.
4. Verify that the "$ORACLE_HOME/dbs/lk<sid>" file does not exist
5. Startup the instance
Solution Explanation:
=====================
The "lk<sid>" and "sgadef<sid>.dbf" files are used for locking shared memory. It seems that even though no memory is allocated, Oracle thinks memory is still locked. By removing the "sgadef" and "lk" files you remove any knowledge oracle has of shared memory that is in use. Now the database can start.
参考资料：
http://blog.itpub.net/12272958/viewspace-716020
http://blog.itpub.net/20674423/viewspace-711545