近期某客户的备机数据库集群ASM磁盘出现问题，数据库系统异常关闭。对问题进行排查，可以发现问题是存储磁盘出现了IO问题后OFFLINE，从而导致磁盘组也OFFLINE。由于系统是备机，发现时已经过去了较长时间，多余NORMAL冗余（或者双活的存储配置）来说，超过REPAIR TIME的断开需要在加回ASM磁盘组时重新同步。
如下是整个分析及处理过程：
1、检查磁盘状态
SQL> select NAME,GROUP_NUMBER,TYPE,state from v$asm_diskgroup;
NAME
GROUP_NUMBER TYPE STATE
test_DBDATA
0 DISMOUNTED
test_OCR
2 NORMAL MOUNTED
2、尝试MOUNT磁盘组的报错
SQL> alter diskgroup all mount;
alter diskgroup all mount
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15040: diskgroup is incomplete
ORA-15042: ASM disk "2" is missing from group number "1"
ORA-15042: ASM disk "1" is missing from group number "1"
ORA-15017: diskgroup "test_OCR" cannot be mounted
ORA-15013: diskgroup "test_OCR" is already mounted
SQL> ALTER DISKGROUP test_DBDATA MOUNT ;
ALTER DISKGROUP test_DBDATA MOUNT
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15040: diskgroup is incomplete
ORA-15042: ASM disk "2" is missing from group number "1"
ORA-15042: ASM disk "1" is missing from group number "1"
3、检查当前的ASM磁盘情况（注意此命令是动态查看磁盘，如果磁盘现在丢失不显示，就不体现在输出，也就是看到的盘的数量，和正常运行时可能不一样，需要注意。）
SQL> set linesize 200 pagesize 200
SQL> col name for a20
SQL> col path for a30
SQL> col HEADER_STATUS for a12
SQL> select NAME,GROUP_NUMBER,HEADER_STATUS,PATH from V$ASM_DISK order by 2,4;
NAME GROUP_NUMBER HEADER_STATU PATH
0 MEMBER /dev/raw/raw6
0 MEMBER /dev/raw/raw7
0 MEMBER /dev/raw/raw8
test_OCR_0001 2 MEMBER /dev/raw/raw5
test_OCR_0002 2 MEMBER /dev/raw/raw9
_DROPPED_0000_test_OC 2 UNKNOWN
4、操作系统日志查看磁盘故障日志
ul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac CDB: Write(10): 2a 00 08 9a 05 1c 00 00 01 00
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac Unhandled error code
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac CDB: Write(10): 2a 00 08 9a 05 1a 00 00 02 00
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac Unhandled error code
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Jul 25 13:26:48 test1 kernel: sd 2:0:1:1: sdac CDB: Write(10): 2a 00 08 9a 05 19 00 00 01 00
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 144311575
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 929664
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 927744
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 1133312
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 1133056
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 930816
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 929792
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 4146944
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 4146688
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 1134464
Jul 25 13:26:48 test1 kernel: sd 2:0:1:2: rejecting I/O to offline device
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 7267456
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 7274992
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 144311573
Jul 25 13:26:48 test1 kernel: end_request: I/O error, dev sdac, sector 144311571
5、查看和修复ASM磁盘
root@test1 rules.d# cat 60-raw.rules
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="360060160076042009e3fff15cc1de711", RUN+="/bin/raw /dev/raw/raw1 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="36006016007604200e69910facb1de711", RUN+="/bin/raw /dev/raw/raw2 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="36006016007604200e4f075cdcb1de711", RUN+="/bin/raw /dev/raw/raw3 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="360060160076042009bc20b31cc1de711", RUN+="/bin/raw /dev/raw/raw4 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="360060160068044001b35a19bd01de711", RUN+="/bin/raw /dev/raw/raw5 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="36006016006804400818e5d63d01de711", RUN+="/bin/raw /dev/raw/raw6 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="360060160068044000b4a946ed01de711", RUN+="/bin/raw /dev/raw/raw7 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="36006016006804400ebb2b17cd01de711", RUN+="/bin/raw /dev/raw/raw8 %N"
ACTION=="add", KERNEL=="sd*", PROGRAM=="/lib/udev/scsi_id --whitelisted --replace-whitespace --device=/dev/$name", RESULT=="360060160068044003f43ddb3851fe711", RUN+="/bin/raw /dev/raw/raw9 %N"
KERNEL=="raw1-9", OWNER="grid", GROUP="asmadmin", MODE="660"
root@test1 rules.d# start_udev
Starting udev: OK
root@test1 rules.d# ls -al /dev/raw/raw*
crw-rw---- 1 grid asmadmin 162, 1 Jul 25 17:23 /dev/raw/raw1
crw-rw---- 1 grid asmadmin 162, 2 Jul 25 17:23 /dev/raw/raw2
crw-rw---- 1 grid asmadmin 162, 3 Jul 25 17:23 /dev/raw/raw3
crw-rw---- 1 grid asmadmin 162, 4 Jul 25 17:23 /dev/raw/raw4
crw-rw---- 1 grid asmadmin 162, 5 Jul 25 17:23 /dev/raw/raw5
crw-rw---- 1 grid asmadmin 162, 6 Jul 25 17:23 /dev/raw/raw6
crw-rw---- 1 grid asmadmin 162, 7 Jul 25 17:23 /dev/raw/raw7
crw-rw---- 1 grid asmadmin 162, 8 Jul 25 17:23 /dev/raw/raw8
crw-rw---- 1 grid asmadmin 162, 9 Jul 25 17:23 /dev/raw/raw9
crw-rw---- 1 root disk 162, 0 Jul 25 17:23 /dev/raw/rawctl
6、查看磁盘并MOUNT磁盘组（此时可以看到全部ASM需要用的磁盘）
SQL> select NAME,GROUP_NUMBER,HEADER_STATUS,PATH from V$ASM_DISK order by 2,4;
NAME GROUP_NUMBER HEADER_STATU PATH
0 MEMBER /dev/raw/raw1
0 MEMBER /dev/raw/raw2
0 MEMBER /dev/raw/raw3
0 MEMBER /dev/raw/raw4
0 MEMBER /dev/raw/raw6
0 MEMBER /dev/raw/raw7
0 MEMBER /dev/raw/raw8
test_OCR_0001 2 MEMBER /dev/raw/raw5
test_OCR_0002 2 MEMBER /dev/raw/raw9
_DROPPED_0000_test_OCR 2 UNKNOWN
MOUNT磁盘组，此时对于DATA磁盘组，整个UMOUNT，此时MOUNT就行：
SQL> ALTER DISKGROUP test_DBDATA MOUNT ;
Diskgroup altered.
对于OCR磁盘组，为NORMAL模式，部分盘OFFLINE，此时加回来就提升报错（参数不支持）：
SQL> ALTER DISKGROUP test_OCR ONLINE DISKS IN FAILGROUP test_OCR_0000 NOWAIT;
ALTER DISKGROUP test_OCR ONLINE DISKS IN FAILGROUP test_OCR_0000 NOWAIT
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15283: ASM operation requires compatible.rdbms of 11.1.0.0.0 or higher
需要强制加回来：
SQL> alter diskgroup test_OCR add disk '/dev/raw/raw4' force;
Diskgroup altered.
也再次提升，双活存储时需要设置compatible.rdbms参数及disk_repair_time参数，来应对这种盘OFFLINE问题。