Posts Tagged ASM lun

TOD – How to check if a LUN is used by ASM

Posted by Jay Caviness in ASM, Tip 'o the day on September 3rd, 2008

ASM is down, init+ASM.ora is gone and you need to see which luns are owned by ASM, if on linux you can generally use the “service oracleasm” command to find the luns that have been marked for use with ASM.  On other platforms the oracleasm service is not available, how then to check?   You can use the od command to check the first few lines of a lun, it will display “ORCLDISK” and the diskgroup in the first five lines if part of and ASM diskgroup:

/dev:()$ od -c /dev/hdiskpower10 | more         
0000000   \0 202 001 001  \0  \0  \0  \0 200  \0  \0  \0 211 341   $ 207
0000020   \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
0000040   O   R   C   L   D   I   S   K  \0  \0  \0  \0  \0  \0  \0  \0
0000060   \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
0000100   \n 020  \0  \0  \0  \0 001 003 D   G   R   O   U   P   1  _
0000120    0   0   0   0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
0000140   \0  \0  \0  \0  \0  \0  \0  \0   D   G   R   O   U   P   1  \0
0000160   \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
0000200   \0  \0  \0  \0  \0  \0  \0  \0   D   G   R   O   U   P   1   _
0000220    0   0   0   0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
0000240   \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0

You can see above that this lun is part of diskgroup dgroup1.

No Comments