【说明】最近整个IT的运气有点背，先是机房的停电事件。最近又发生了一个事故，有台虚拟机的硬盘坏掉了，导致安装在虚拟机上面的应用和数据库全部起不来了。经过一番折腾虚拟机终于起来了，但是启动的时候报错了：
SQL> startup
Oracle instance started.
Total System Global Area 6747725824 bytes
Fixed Size 2213976 bytes
Variable Size 4362078120 bytes
Database Buffers 2348810240 bytes
Redo Buffers 34623488 bytes
Database mounted.
ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1],[6674], [13272], [13337], [], [], [], [], [], [], []
alert报警日志如下：
Recovery of Online Redo Log: Thread 1 Group 2 Seq 6674 Reading mem 0
Mem# 0: /oracle/oradata/klekpj/redo02.log
Media Recovery Complete (klekpj)
Completed: alter database recover if needed
start
Tue Jun 23 16:11:45 2015
alter database open
Beginning crash recovery of 1 threads
parallel recovery started with 7 processes
Started redo scan
Completed redo scan
read 1900 KB redo, 0 data blocks need recovery
Errors in file /oracle/diag/rdbms/klekpj/klekpj/trace/klekpj_ora_19307.trc (incident=9755):
ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [6674], [13272], [13337], [], [], [], [], [], [], []
Incident details in: /oracle/diag/rdbms/klekpj/klekpj/incident/incdir_9755/klekpj_ora_19307_i9755.trc
Aborting crash recovery due to error 600
Errors in file /oracle/diag/rdbms/klekpj/klekpj/trace/klekpj_ora_19307.trc:
ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [6674], [13272], [13337], [], [], [], [], [], [], []
Errors in file /oracle/diag/rdbms/klekpj/klekpj/trace/klekpj_ora_19307.trc:
ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [6674], [13272], [13337], [], [], [], [], [], [], [
解决方法：
SQL> startup mount;
ORACLE instance started.
Total System Global Area 6747725824 bytes
Fixed Size 2213976 bytes
Variable Size 4362078120 bytes
Database Buffers 2348810240 bytes
Redo Buffers 34623488 bytes
Database mounted.
SQL> recover database using backup controlfile until cancel;
ORA-00279: change 1974040004 generated at 06/10/2015 16:04:16 needed for thread
1
ORA-00289: suggestion : /oracle/arch/1_6674_829596422.dbf
ORA-00280: change 1974040004 for thread 1 is in sequence #6674
Specify log: {=suggested | filename | AUTO | CANCEL}
CANCEL
Media recovery cancelled.
SQL> alter database open resetlogs;
Database altered.
数据库成功打开了
原因分析：
ALTER DATABASE RECOVER database using backup controlfile until cancel
Media Recovery Start
started logmerger process
Parallel Media Recovery started with 8 slaves
ORA-279 signalled during: ALTER DATABASE RECOVER database using backup controlfile until cancel ...
Tue Jun 23 16:56:20 2015
ALTER DATABASE RECOVER CANCEL
Media Recovery Canceled
Completed: ALTER DATABASE RECOVER CANCEL
alter database open resetlogs
Archived Log entry 6334 added for thread 1 sequence 6673 ID 0xf5f2c983 dest 1:
Tue Jun 23 16:56:31 2015
Archived Log entry 6335 added for thread 1 sequence 6674 ID 0xf5f2c983 dest 1:
Archived Log entry 6336 added for thread 1 sequence 6672 ID 0xf5f2c983 dest 1:
RESETLOGS after incomplete recovery UNTIL CHANGE 1974040004
因为服务器的异常断电导致LGWR写ONLINE REDOLOG文件失败，当然数据也没有写入到数据文件中。下次启动数据库的时候需要做异常恢复，但是从ONLINE REDOLOG里面读取这些REDO信息的时候又找不到，所以打开的时候就报错了。
ORA-00600: internal error code, arguments: [kcratr_nab_less_than_odr], [1], [6674], [13272], [13337], [], [], [], [], [], [], []
数据进行恢复的时候，需要从onine redo log 1seq#6674的log，从13272恢复到13337。
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