4.检查两节点磁盘主次设备号与对应的磁盘信息正确:
mknod /dev/asmdisk/datadisk1 c 265 8 对应 /devices/virtual-devices@100/channel-devices@200/disk@1:a,raw
mknod /dev/asmdisk/datadisk2 c 265 16 对应 /devices/virtual-devices@100/channel-devices@200/disk@2:a,raw
mknod /dev/asmdisk/datadisk3 c 265 24 对应 /devices/virtual-devices@100/channel-devices@200/disk@3:a,raw
mknod /dev/asmdisk/datadisk4 c 265 32 对应 /devices/virtual-devices@100/channel-devices@200/disk@4:a,raw
5.回过头检查alert.log日志如下片段：
ORA-27041: unable to open file
SVR4 Error: 13: Permission denied
说明存在权限问题。
6.查看OS用户和组的情况：
cd /etc/passwd
ccssver:x:1001:106::/mdccssver/mdccssver/home:/bin/bash
oragrid:x:1002:106::/mdccssver/oragrid/home:/bin/bash
cat /etc/group
oinstall::106:
7.查看mknod设备权限
-bash-4.1$ cd /dev/asmdisk
-bash-4.1$ ls -ltr
total 0
crw-rw-r-- 1 oragrid asmadmin 265, 24 Sep 14 13:51 datadisk3
crw-rw-r-- 1 oragrid asmadmin 265, 16 Sep 14 13:51 datadisk2
crw-rw-r-- 1 oragrid asmadmin 265, 8 Sep 14 13:51 datadisk1
crw-rw-r-- 1 oragrid asmadmin 265, 32 Sep 14 13:51 datadisk4
crw-rw-r-- 1 oragrid asmadmin 265, 70 Sep 15 03:29 crsdisk4
crw-rw-r-- 1 oragrid asmadmin 265, 62 Sep 15 03:29 crsdisk3
crw-rw-r-- 1 oragrid asmadmin 265, 54 Sep 15 03:29 crsdisk2
crw-rw-r-- 1 oragrid asmadmin 265, 78 Sep 15 03:29 crsdisk5
crw-rw-r-- 1 oragrid asmadmin 265, 46 Sep 15 03:29 crsdisk1
从上面看，应该权限设置有问题，mknod设备的组应该为oinstall，所以直接手工启动库会有问题，但用srvctl启动库是正常的。如下：
-bash-4.1$ srvctl start instance -d ccssver -i ccssver2
-bash-4.1$ ps -ef|grep pmon
oragrid 25198 1 0 13:51:07 ? 0:09 asm_pmon_+ASM2
ccssver 8819 1 0 03:39:40 ? 0:00 ora_pmon_ccssver2
ccssver 9646 7843 0 03:40:27 pts/3 0:00 grep pmon
oragrid 25935 1 0 13:51:44 ? 0:07 mdb_pmon_-MGMTDB
-bash-4.1$ id
uid=1001(ccssver) gid=106(oinstall)
-bash-4.1$ sqlplus /nolog
SQL*Plus: Release 12.1.0.2.0 Production on Thu Sep 15 03:40:56 2016
Copyright (c) 1982, 2014, Oracle. All rights reserved.
SQL> conn /as sysdba
Connected.
SQL> select open_mode from v$database;
OPEN_MODE
--------------------
READ WRITE