On Wednesday, 12/02/2009 at 07:37 EST, Charles Grady 
<[email protected]> wrote:
> OK.  I have a z/VM vol that contains a 'full pack' mdisk for a linux 
guest.
> when trying to back up this vol from z/OS with DFDSS he complains about
> there not being a valid VTOC.  IS there a way to just "clip" the VTOC to 
get the
> information in the right format and NOT distroy the data. The mdisk is 
cyl 
> 0001-3337 on volid NLNX0A.

Do not clip a volume that z/OS doesn't own.

BTW, an mdisk that starts on cyl 1 is not a "full pack" mdisk.  That means 
that if your z/OS is running in an LPAR, it will see real cyl 0 (owned by 
CP in this example), not cyl 1 (owned by Linux).

Caveat emptor: External backups of a live Linux guest will be fuzzy.  That 
is, incomplete and inconsistent, just as a z/OS backup would be if taken 
using DDR on CMS while z/OS is running.  Build your backup/restore 
procedures accordingly.  (Best is to shut down the Linux guest and then 
copy the disks.)

Alan Altmark
z/VM Development
IBM Endicott

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