数据库实例日志：

Tue Mar 01 12:18:12 2016

SUCCESS: diskgroup ORADISKGRP1 was dismounted

Errors in file C:\APP\ORACLE\PRODUCT\\diag\rdbms\bflex\bflex1\trace\bflex1_ckpt_:

ORA-00206: error in writing (block 3,# blocks 1) of control file

ORA-00202: control file: '+ORADISKGRP1/bflex/controlfile/'

ORA-15078: ASM diskgroup was forcibly dismounted

再看asm日志

ASM Health Checker found 1 new failures

Dirty Detach Reconfiguration complete

Tue Nov 01 12:18:12 2016

WARNING: dirty detached from domain 1

NOTE: cache dismounted group 1/0x5DD073B7 (ORADISKGRP1)

sql> alter diskgroup ORADISKGRP1 dismount force /* ASM SERVER:1573942199 */

NOTE: cache deleting context for group ORADISKGRP1 1/0x5dd073b7

GMON dismounting group 1 at 6 for pid 30,osid 7684

NOTE: Disk ORADISKGRP1_0000 in mode 0x7f marked for de-assignment

NOTE: Disk ORADISKGRP1_0001 in mode 0x7f marked for de-assignment

NOTE: Disk ORADISKGRP1_0002 in mode 0x7f marked for de-assignment

SUCCESS: alter diskgroup ORADISKGRP1 dismount force /* ASM SERVER:1573942199 */

SUCCESS: ASM-initiated MANDATORY DISMOUNT of group ORADISKGRP1

这里的asm日志很明显由于asm disk无法正常访问,报ORA-27072错误,磁盘组被强制dismount. 一般出现这样故障的原因大多都是人为误操作造成的，比如挂到A机的裸盘被挂至B机，然后被误格式化。

处理办法：

先用kfed恢复磁盘头

使用asmtool -list查看相关磁盘信息

然后用@H_301_192@dbv检测是否有坏块，没有就好办了。幸好asm有备份，用备份恢复即可。