On Tuesday, 01/23/2007 at 09:19 EST, David Boyes <[EMAIL PROTECTED]> wrote: > One area that might be interesting would be to investigate a Linux > device driver using CP *BLOCKIO services for disk I/O instead of > directly addressing the disks. There would be a performance impact, but > the additional layer of isolation would effectively remove any disk > geometry-sensitive components in the I/O layer, and it would have the > side effect of putting a lot more of the I/O state in a place where CP > could get at it more effectively. Of course, that introduces a problem > with moving IUCV connections, but I think that's relatively easily > solvable (ie what to do if a IUCV sever occurs and how to redrive the > I/O request transparently).
I would suggest that eligibility for migration would require that the user have an identical directory on the target system. This ensures that disk geometries, network connections, memory size, CPUs, etc. are unchanged. While you might be able to construct scenarios where this is not necessarily required, managing the edge cases would be painful. There is no need to abstract the I/O layer another level. And the underlying rdevs need to be the same disks, whether shared or mirrored in some way. Alan Altmark z/VM Development IBM Endicott
