[Info-vax] image backup on itanium

[Stephen Hoffman]

On 2015-05-02 20:58:10 +0000, Hans Vlems said:

> an image backup also keeps track of linked directories, it knows about 
> set file/enter.
> AFAIK copy is unaware of that and would produce a much larger footprint 
> than backup does.

Neither COPY nor BACKUP /NOIMAGE is appropriate for and neither will 
work particularly well for system disks on any of the three 
architectures.  Not without additional assistance after restoration, 
and prior to attempting a bootstrap.  You'll end up with replicated 
files and missing linkages, and probably also with some degree of 
creeping system management confusion ensuing.

Further, neither COPY nor BACKUP /NOIMAGE will correctly deal with the 
OpenVMS I64 boot data structure file placements.  Neither GPT nor the 
diagnostic partition will be correctly recreated.    Recreating these 
files on an existing system disk is technically possible — if you can 
move stuff around — but is not easy.

The BACKUP /IMAGE mechanism is the documented means, and provides what 
is necessary here with the assistance of the sys$setbootshr callable 
API.

> Or did Guy Peleg improve Copy?

No.  COPY does not special-process directory aliases, nor does it 
manage file placements necessary for OpenVMS I64.   There's just no 
logic for that in COPY.



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