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故障现象：
ORALCE启动时报如下错误：

ORA-03113: end-of-file on communication channel
SQL> startup
ORACLE instance started.

Total System Global Area 3657797632 bytes
Fixed Size 2258600 bytes
Variable Size 2013268312 bytes
Database Buffers 1627389952 bytes
Redo Buffers 14880768 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 2118
Session ID: 401 Serial number: 5

SQL> startup mount;
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
原因查找：
查看orcle启动日志，确定具体是什么原因引起的错误。
cd $ORACLE_HOME/diag/rdbms/ncdbemu/ncdbemu/trace/
ls -alcr | grep alert (c时间排序、r倒序) 定位启动日志。打开很长内容，不好找。因此用跟踪来找。

tail -f -n 500 alert_ncdbemu.log 然后重启运行上面的startup命令，跟踪得到如下内容。

ARC3 started with pid=23, OS id=2126
Errors in file /oracle/app/oracle/diag/rdbms/ncdbemu/ncdbemu/trace/ncdbemu_ora_2118.trc:
ORA-19815: WARNING: db_recovery_file_dest_size of 20971520000 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.
************************************************************************
ARCH: Error 19809 Creating archive log file to '/backup/fast_recovery_area/NCDBEMU/archivelog/2016_02_01/o1_mf_1_603_%u_.arc'
Errors in file /oracle/app/oracle/diag/rdbms/ncdbemu/ncdbemu/trace/ncdbemu_ora_2118.trc:
ORA-16038: log 3 sequence# 603 cannot be archived
ORA-19809: limit exceeded for recovery files
ORA-00312: online log 3 thread 1: '/dbdata/oradata/ncdbemu/redog03m01.rdo'
ORA-00312: online log 3 thread 1: '/dbdata/oradata/ncdbemu/redog03m02.rdo'
USER (ospid: 2118): terminating the instance due to error 16038
System state dump requested by (instance=1, osid=2118), summary=[abnormal instance termination].
System State dumped to trace file /oracle/app/oracle/diag/rdbms/ncdbemu/ncdbemu/trace/ncdbemu_diag_2087_20160201162949.trc
Dumping diagnostic data in directory=[cdmp_20160201162949], requested by (instance=1, osid=2118), summary=[abnormal instance termination].
Instance terminated by USER, pid = 2118
Mon Feb 01 16:33:49 2016
Starting ORACLE instance (normal)
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Initial number of CPU is 2
CELL communication is configured to use 0 interface(s):
CELL IP affinity details:
NUMA status: non-NUMA system
cellaffinity.ora status: N/A
CELL communication will use 1 IP group(s):
Grp 0:
Picked latch-free SCN scheme 3
Using LOG_ARCHIVE_DEST_1 parameter default value as USE_DB_RECOVERY_FILE_DEST
Autotune of undo retention is turned on.
IMODE=BR
ILAT =88
LICENSE_MAX_USERS = 0
SYS auditing is disabled
Starting up:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options.
ORACLE_HOME = /oracle/app/oracle/dbhome
System name: Linux
Node name: NcDbEmulator
Release: 2.6.32-431.el6.x86_64
Version: #1 SMP Sun Nov 10 22:19:54 EST 2013
Machine: x86_64
Using parameter settings in server-side spfile /oracle/app/oracle/dbhome/dbs/spfilencdbemu.ora
System parameters with non-default values:
processes = 500
sessions = 800
memory_target = 3504M
control_files = "/dbdata/oradata/ncdbemu/control01.ctl"
control_files = "/backup/fast_recovery_area/ncdbemu/control02.ctl"
control_files = "/dbdata/oradata/ncdbemu/control03.ctl"
db_block_size = 8192
compatible = "11.2.0.4.0"
log_archive_format = "%t_%s_%r.dbf"
cluster_database = FALSE
db_recovery_file_dest = "/backup/fast_recovery_area"
db_recovery_file_dest_size= 20000M
undo_tablespace = "UNDOTBS1"
remote_login_passwordfile= "EXCLUSIVE"
db_domain = ""
dispatchers = "(PROTOCOL=TCP) (SERVICE=ncdbemuXDB)"
job_queue_processes = 1000
audit_file_dest = "/oracle/app/oracle/admin/ncdbemu/adump"
audit_trail = "DB"
db_name = "ncdbemu"
open_cursors = 300
diagnostic_dest = "/oracle/app/oracle"
4、解决办法
有三个：（其实上面日志中已经给出4个解决方法了。）
1）将归档设置到其他目录，修改alter system set log_archive_dest = 其他路径
2）转移或者删除闪回恢复区里的归档日志。
3）增大闪回恢复区。alter system set db_recovery_file_dest_size=30G;
第二个错误（24324和01041）的解决：

只要退出sqlplus然后重新登录就可以了。
5、解决步骤：
1）启动到mount状态下，
SQL> startup mount;
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SQL> startup nomount
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
[oracle@NcDbEmulator ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Feb 1 16:33:44 2016

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

Connected to an idle instance.

SQL> startup mount;
ORACLE instance started.

Total System Global Area 3657797632 bytes
Fixed Size 2258600 bytes
Variable Size 2013268312 bytes
Database Buffers 1627389952 bytes
Redo Buffers 14880768 bytes
Database mounted.
2）查看恢复区（闪回区）位置及大小：
SQL> show parameter db_recovery;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string /backup/fast_recovery_area
db_recovery_file_dest_size big integer 20000M
SQL> show parameter flashback;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_flashback_retention_target integer 1440
SQL> select file_type,PERCENT_SPACE_USED,NUMBER_OF_FILES from v$flash_recovery_area_usage;

FILE_TYPE PERCENT_SPACE_USED NUMBER_OF_FILES
-------------------- ------------------ ---------------
CONTROL FILE 0 0
REDO LOG 0 0
ARCHIVED LOG 99.85 595
BACKUP PIECE 0 0
IMAGE COPY 0 0
FLASHBACK LOG 0 0
FOREIGN ARCHIVED LOG 0 0

7 rows selected.
3）方法一，修改恢复区大小：
SQL> alter system set db_recovery_file_dest_size=30G;

System altered.

SQL> show parameter db_recovery_file_dest_size;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest_size big integer 30G
4）开启数据库
SQL> alter database open;

Database altered.