[Oracleasm-users] Shifting from OCFS2 to ASM

[Joel Becker]

On Fri, Jun 19, 2009 at 12:29:01AM +0300, Karim Alkhayer wrote:
> 1.    In note 602952.1, it seems to be possible to create the ASMLIB disks
> on /dev/mapper/*  
> 
> Example (same note): # /etc/init.d/oracleasm createdisk VOL1
> /dev/mapper/mpath2p1

	Of course it is.  /dev/mapper/mpath2p1 actually points to a dm-N
device.  They are different paths for the same thing.  You can use any
of the paths for a thing to create it.  The issue of 'dm-*' vs
'mapper/*' naming only comes up when scanning disks on reboot.

> 2.    I don't really understand the need to actually create a partition out
> of a LUN in order to use it; can't I just use the entire disk immediately?
> If no, why?

	Oracle declares that whole disks are verboten.  They don't want
people accidentally fdisking the LUN and overwriting the ASM header.

Joel

-- 

"I'm drifting and drifting
 Just like a ship out on the sea.
 Cause I ain't got nobody, baby,
 In this world to care for me."

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127