模拟bootstrap$坏块故障
bootstap$表在数据库启动的时候初始化其它数据字典表，类似于linux下的init.d，如果bootstap$损坏那么就无法启动数据库，我使用dd命令来修复损坏的数据块。
数据库版本10.2.0.1.0
[oracle@ora10-single-01 ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.5.0 - Production on Sat Jun 28 16:25:57 2014
Copyright (c) 1982, 2010, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> select status from v$instance;
STATUS
------------
OPEN
SQL> Alter session set events '10912 trace name context forever, level 1';
Session altered.
SQL> exec dbms_space_admin.tablespace_fix_segment_extblks('SYSTEM');
PL/SQL procedure successfully completed.
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 281018368 bytes
Fixed Size 2095672 bytes
Variable Size 180356552 bytes
Database Buffers 92274688 bytes
Redo Buffers 6291456 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection forced
SQL> startup
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SQL> alter database open;
ERROR:
ORA-03114: not connected to ORACLE
数据库起不来了，查看alert日志：
Successful open of redo thread 1 Sat Jun 28 16:26:45 CST 2014 MTTR advisory is disabled because FAST_START_MTTR_TARGET is not set Sat Jun 28 16:26:45 CST 2014 ARC1: Becoming the 'no FAL' ARCH ARC1: Becoming the 'no SRL' ARCH Sat Jun 28 16:26:45 CST 2014 ARC0: Becoming the heartbeat ARCH Sat Jun 28 16:26:45 CST 2014 SMON: enabling cache recovery Sat Jun 28 16:26:45 CST 2014 Errors in file /oracle/admin/suq/udump/suq_ora_3112.trc: ORA-00600: internal error code, arguments: [4000], [6], [], [], [], [], [], [] Sat Jun 28 16:26:47 CST 2014 Errors in file /oracle/admin/suq/udump/suq_ora_3112.trc: ORA-00704: bootstrap process failure ORA-00600: internal error code, arguments: [4000], [6], [], [], [], [], [], [] Sat Jun 28 16:26:47 CST 2014 Error 704 happened during db open, shutting down database USER: terminating instance due to error 704 Instance terminated by USER, pid = 3112 ORA-1092 signalled during: ALTER DATABASE OPEN...
查看trace文件：
KSFD PGA DUMPS Number of completed I/O requests=0 flags=1 END OF PROCESS STATE --------------------- PINNED BUFFER HISTORY (oldest pin first) --------------------- BH (0x65ffcad8) file#: 1 rdba: 0x00400179 (1/377) class: 4 ba: 0x65fd8000 --从这里知道是1号文件的第377数据块有问题 set: 3 blksize: 8192 bsi: 0 set-flg: 2 pwbcnt: 0 dbwrid: 0 obj: 56 objn: 56 tsn: 0 afn: 1 hash: [65ffcbe8,6df6c540] lru: [65ffcc68,6d8bee40] ckptq: [NULL] fileq: [NULL] objq: [687efa48,687efa48] st: XCURRENT md: NULL tch: 1 flags: LRBA: [0x0.0.0] HSCN: [0xffff.ffffffff] HSUB: [65535] buffer tsn: 0 rdba: 0x00400179 (1/377) scn: 0x0000.000c1fc3 seq: 0x01 flg: 0x04 tail: 0x1fc31001 frmt: 0x02 chkval: 0xe7c8 type: 0x10=DATA SEGMENT HEADER - UNLIMITED Hex dump of block: st=0, typ_found=1
从一个相同版本的数据上dd一个好的377号数据块
[oracle@ora10-single-01 suq]$ dd if=system01.dbf of=/home/oracle/1 skip=377 bs=8192 count=1 #skip用来跳过多少数据块 1+0 records in 1+0 records out 8192 bytes (8.2 kB) copied, 9.3308e-05 seconds, 87.8 MB/s
将文件传到出问题的主机，将这个文件dd进1号数据文件
[oracle@ora10-single-01 suq]$ dd if=1 of=system01.dbf seek=377 bs=8192 count=1 conv=notrunc #使用notrunc不会删除之后的数据，否则第377块后面的数据就被清空了，seek定位到第377个块，做之前先备份文件 1+0 records in 1+0 records out 8192 bytes (8.2 kB) copied, 8.5765e-05 seconds, 95.5 MB/s
打开数据库试试吧
[oracle@ora10-single-01 ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sat Jun 28 17:44:25 2014 Copyright (c) 1982, 2010, Oracle. All Rights Reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 281018368 bytes Fixed Size 2095672 bytes Variable Size 180356552 bytes Database Buffers 92274688 bytes Redo Buffers 6291456 bytes Database mounted. ORA-01113: file 1 needs media recovery if it was restored from backup, or END BACKUP if it was not ORA-01110: data file 1: '/oracle/oradata/suq/system01.dbf' SQL> recover datafile 1 Media recovery complete. SQL> alter database open; Database altered.
参考LUNAR的博客。。。