Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 4907
Session ID: 1 Serial number: 5
这种错误的解决方案
出现这个报错之后，明明oracle已经mount，此时查看oracle的状态：
select open_mode from v$database;
ERROR:
ORA-03114: not connected to ORACLE
提示oracle就根本没有连接到oracle
1，此时先查看alert日志
$locate alert_orcl.log（我实例名是orcl）
/u01/app/oracle/diag/rdbms/orcl/orcl/trace/alert_orcl.log
发现alter日志报错：
ORA-19815: WARNING: db_recovery_file_dest_size of 4039114752 bytes is 100.00% used, and has 0 remaining bytes available.
************************************************************************
You have following choices to free up space from recovery area:
1. Consider changing RMAN RETENTION POLICY. If you are using Data Guard,
then consider changing RMAN ARCHIVELOG DELETION POLICY.
2. Back up files to tertiary device such as tape using RMAN
BACKUP RECOVERY AREA command.
3. Add disk space and increase db_recovery_file_dest_size parameter to
reflect the new space.
4. Delete unnecessary files using RMAN DELETE command. If an operating
system command was used to delete files, then use RMAN CROSSCHECK and
DELETE EXPIRED commands.
************************************************************************
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_4907.trc:
************************************************************************
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim 44462592 bytes disk space from 4039114752 limit
*** 2014-08-24 17:04:51.935 4132 krsh.c
ARCH: Error 19809 Creating archive log file to ‘/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2014_08_24/o1_mf_1_117_%u_.arc‘
由于db_recovery_file_dest_size定义的闪回空间全部用完了，而导致了oracle无法自动归档！！！而且oracle给出了四中解决建议
2，进入闪回空间看看闪回的使用情况
目录：/u01/app/oracle/flash_recovery_area/ORCL/archivelog
发先此时已经无法删除，只能将由db_recovery_file_dest_size定义的闪回区域（FRA）增大，而且由于db现在提示无法连接到oracle，所有修改spfile是没有可能的（即是通过alter system set来完成），只能修改pfile，从pfile打开db（pfile是文本文件，直接修改，spfile是二进制文件，只能通过alter system 来完成修改）
3，修改pfile
cd /u01/app/oracle/admin/orcl/pfile/
vi init.ora
直接改：*.db_recovery_file_dest_size=8039114752
4，然后从pfile启动数据库
startup pfile=‘/u01/app/oracle/admin/orcl/pfile/init.ora‘
在用pfile从新生成spfile