Re: geometry of dm devices......

["Darrick J. Wong" <djwong@us.ibm.com>]

[-- Attachment #1.1: Type: text/plain, Size: 715 bytes --]

Peter Koutoupis wrote:

>> I understand the HDIO_GETGEO is an unsupported feature to dm 
>> devices....but under normal practices how would a normal end-user be 
>> able to obtain such geometry from a raw dm device?  I have read of 

Wow, I'm late to the game.  If your kernel/software are new enough, you
can set a dm device's geometry via the DM_DEV_SET_GEOMETRY_CMD ioctl.
iirc, the userland equivalent is:

# dmsetup setgeometry /dev/foo cyl head spt start

...after which HDIO_GETGEO should return nonzero values.

You'll need kernel 2.6.16+ and I think the requisite version of dmsetup
is 1.02.  And to my (very limited) knowledge of multipath, geometry is
not set up automatically.

--D


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 191 bytes --]

[-- Attachment #2: Type: text/plain, Size: 0 bytes --]