[Info-vax] 'Partitioning' raid controller for VMS on Integrity

[Simon Clubley]

On 2021-09-09, Bob Gezelter <gezelter at rlgsc.com> wrote:
>
> The original supra-volume solution was and is FILES-11 volume sets. Supported since the beginning, and still useful for a variety of purposes.
>
> Host-based Volume Shadowing allows the creation of shadow-sets, including single volume shadow sets, which can be expanded dynamically for various purposes, e.g. volume changeover, volume expansion, and backup.
>
> There is also the LD facility, which allows one to create virtual volumes within an overarching volume structure, which can be used to effectively "partition" a disk volume, e.g. create a logical disk, then make the file contiguous. I have used this "file system within a file system" to create disks with different cluster factors for different uses, e.g., one file system for sources, command files, and other user programs, with a relatively small cluster factor, side by side or within a file structure with a 
> cluster factor more attuned to large (multi-gigabyte) database or other files.
>

Bob,

The VMS-hosted options you list above are all in the wrong direction
_if_ the goal is to make use of larger disk sizes than VMS supports.

What does actually happen if you try to initialise a (say) 8TB disk
with an ODS-2/ODS-5 filesystem ?

Do you get a disk is too big error message ?

Does VMS just use the first 2TB of the volume and ignore the rest ?

Does it try to create a 8TB filesystem anyway and then either hang or
create an invalid filesystem ?

I've never tried it so I don't know.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.