Re: [Evms-devel] RE: trouble recovering raid5 array (more info at the bottom)

[Steve D. <st...@us...>]

"Steinar H. Gunderson" <sgu...@bi...> wrote on 11/23/2005
02:02:34 PM:

> On Wed, Nov 23, 2005 at 01:56:35PM -0600, Steve Dobbelstein wrote:
> > Yes, you should use the EVMS nodes, not the raw devices.  EVMS built
the
> > array using its own nodes.  Technically, the nodes go to the same place
on
> > the disk, but using two different nodes to access the same area of the
disk
> > is asking for trouble.  Stick with the EVMS nodes when building EVMS
> > volumes.
>
> Don't they also have a different size?

No, the nodes are the same size.  For example, /dev/sda5 and
/dev/evms/.nodes/sda5 point to the same partition on the disk -- same
offset on the disk, same size.  /dev/sda5 will point to major:minor 8:5
which is the device created by the kernel's partitioning code.
/dev/evms/.nodes/sda5 will point to a major:minor such as 254:3 which is a
device created by device-mapper that points to the same place on sda.  (The
minor number will vary based on when the device was created, since
device-mapper minors are dynamically allocated.)

Steve D.