DBCA建库找不到ASM磁盘一例

• 环境信息
  red hat linux64
  gi 11.2.0.4
  oracle 11.2.0.4

• 问题现象
  安装完gi软件及oralce database软件之后，通过dbca用户界面建立数据库，发现在node1上数据库能正常建立，在node2上不能正常建立数据库，dbca建库过程在node2上报错
  如图：
  

• 查看node1和node2上磁盘组状态

node1:
su - grid
SQL> select name,state from v$asm_diskgroup;

NAME                           STATE
------------------------------ -----------
SYSDG                          MOUNTED
DATADG                         MOUNTED
node2:
SQL> select name,state from v$asm_diskgroup;

NAME                           STATE
------------------------------ -----------
SYSDG                          MOUNTED
DATADG                         MOUNTED
通过asmcmd命令查看，能正常看到asm磁盘组里面的文件 

• 通过截图报错查看dbca日志和所示的oraagent_oracle.log
  dbca日志
  /app/oracle/cfgtoollogs/dbca/RAC
  /app/grid/11.2.0/log/rac2/agent/crsd/oraagent_oracle

[Thread-200] [ 2016-09-07 16:29:32.180 CST ] [DatabaseImpl.crsResource:3608]  calling parent's crsResource
[Thread-200] [ 2016-09-07 16:29:32.931 CST ] [PostDBCreationStep.executeImpl:885]  Starting Database HA Resource
[Thread-200] [ 2016-09-07 16:30:24.426 CST ] [CRSNative.internalStartResource:389]  Failed to start resource: Name: ora.rac.db, node: null, filter: null, msg CRS-5017: The resource action "ora.rac.db start" encountered the following error:
ORA-01078: failure in processing system parameters
ORA-01565: error in identifying file '+DATADG/RAC/spfileRAC.ora'
ORA-17503: ksfdopn:2 Failed to open file +DATADG/RAC/spfileRAC.ora
ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
Linux-x86_64 Error: 13: Permission denied
Additional information: 26
Additional information: 196613
. For details refer to "(:CLSN00107:)" in "/app/grid/11.2.0/log/rac2/agent/crsd/oraagent_oracle/oraagent_oracle.log".

CRS-2674: Start of 'ora.rac.db' on 'rac2' failed
CRS-2632: There are no more servers to try to place resource 'ora.rac.db' on that would satisfy its placement policy
[Thread-200] [ 2016-09-07 16:30:24.427 CST ] [PostDBCreationStep.executeImpl:893]  Exception while Starting with HA Database Resource PRCR-1079 : Failed to start resource ora.rac.db
CRS-5017: The resource action "ora.rac.db start" encountered the following error:
ORA-01078: failure in processing system parameters
ORA-01565: error in identifying file '+DATADG/RAC/spfileRAC.ora'   提示无法访问spfile文件
ORA-17503: ksfdopn:2 Failed to open file +DATADG/RAC/spfileRAC.ora
ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
Linux-x86_64 Error: 13: Permission denied
Additional information: 26
Additional information: 196613
. For details refer to "(:CLSN00107:)" in "/app/grid/11.2.0/log/rac2/agent/crsd/oraagent_oracle/oraagent_oracle.log".

CRS-2674: Start of 'ora.rac.db' on 'rac2' failed

日志提示无法访问spfile文件，但是能通过grid用户在磁盘组里发现这些文件，诡异。
那么思考原因：
dbca建立数据库是oracle用户操作，而grid用户是管理磁盘组的，明显现象是，在节点2上oracle用户无法读取或访问asm磁盘组的文件，所以才可能出现此问题

• 进一步验证此想法
  在node2上尝试dbca建立数据库，发现选择数据文件存放路径时，找不到asm磁盘组+DATADG
  

• 至此，问题明确，oracle无法发现asm磁盘组
  查看两节点的oracle用户权限：

node1 :
id oracle
uid=501(oracle) gid=5001(oinstall) 组=5001(oinstall),5002(dba),5003(oper),5006(asmdba)
node2:
uid=501(oracle) gid=5001(oinstall) 组=5001(oinstall),5002(dba),5003(oper),5006(asmdba)

查看GRID_HOME和ORACLE_HOME的bin目录下oracle文件的权限：

node1:
cd $GRID_HOME/bin
ls -l oracle
-rwsr-s--x 1 grid oinstall 209914519 9月   7 14:40 oracle   文件权限正确
node2:
ls -lrt oralce
-rwxr-x--x 1 grid oinstall 209914519 9月   7 14:42 oracle   文件权限错误
oracle用户：
cd $ORACLE_HOME/bin
ls -l oracle
node1:
-rwsr-s--x 1 oracle asmadmin 239626689 9月   7 15:56 oracle  正确
node2:
-rwsr-s--x 1 oracle asmadmin 239626689 9月   7 16:04 oracle  正确

问题明确：
在node2的，GRID_HOME/bin目录下，oracle文件权限错误
修改：
chmod +s oracle
重新回到DBCA建库界面继续执行，则会成功发现ASM磁盘组，并成功建库。