CLSU-00100: Operating System function: open failed failed with error data: 13

Nothing special. I removed some old folder in ASM DiskGroup (after I dropped database but not clean) by using asmcmd command-line. but error.

$ env |grep ORACLE
ORACLE_SID=+ASM1
ORACLE_HOME=/u01/app/11.2.0/grid

$ asmcmd
ASMCMD>
.
.
.
ASMCMD> rm -rf ARCHIVELOG
Can't open '/u01/app/11.2.0/grid/log/diag/asmcmd/user_root/exadb01/alert/alert.log' for append
CLSU-00100: Operating System function: open failed failed with error data: 13
CLSU-00101: Operating System error message: Permission denied
CLSU-00103: error location: SlfFopen1

Error "CLSU-00100: Operating System function: open failed failed with error data: 13", and then checked.

$ cat /u01/app/11.2.0/grid/log/diag/asmcmd/user_root/exadb01/alert/alert.log
25-May-11 17:51 Connected to an idle instance.
25-May-11 17:51 ASMCMD-08102: no connection to ASM; command requires ASM to run

Check both $ORACLE_HOME and $ORACLE_SID environments again -) So... Grant sysasm to sys.

$ sqlplus / as sysasm
SQL*Plus: Release 11.2.0.2.0 Production on Wed May 25 18:10:02 2011
Copyright (c) 1982, 2010, Oracle. All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

SQL> grant sysasm to sys;

Grant succeeded.

Then I removed again.

$ asmcmd
ASMCMD>
.
.
.
ASMCMD> rm -rf ARCHIVELOG
< no error and done >

I can remove directories and files in ASM DiskGroup.