[Ocfs2-users] How to mount OCFS2 file systems using the EMC Power Path multipath device

[Joel Becker]

On Wed, Jun 10, 2009 at 12:22:03PM -0500, Sridhar Avantsa wrote:
> OEL 5, OCFS 1.4, using EMC Power Path for multi pathing.
> 
> I want t mount the OCFS2 file system on the emc power path device.
> I can mount by UUID, and not have to worry about persistent bindings across
> nodes.
> But how do I make sure when it mounts by UUID , that the pwoer path device
> is used.
> 
> Any help will be much appreciated.

	There are two things you can do.  The first is to not worry,
because PP takes over all devices.  That is, if 'sda' and 'sdb' are two
paths of 'emcpowera', it doesn't matter whether you open /dev/sda1,
/dev/sdb1, or /dev/emcpowera1.  PP has hijacked the devices and is used
in all cases.
	Now, a lot of people consider this to be unkosher and wish that
PP didn't hijack the devices.  Maybe in the future EMC will change this.
You can, of course, not worry about it until they do.
	The other alternative is to use udev to ensure you have a device
name that points to the right device.  Then you just mount by the device
name.  For example, a udev rule that only triggers on 'emcpower*'
devices, checks that they are ocfs2 volumes, and then creates
/dev/mydisks/<uuid> for them.

Joel

-- 

Life's Little Instruction Book #396

	"Never give anyone a fruitcake."

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