[Info-vax] Sizing up Disks with Shadowing

[Ken Fairfield]

On Aug 11, 10:44 am, jbriggs444 <jbriggs... at gmail.com> wrote:
> On Aug 10, 4:13 pm, Ken Fairfield <ken.fairfi... at gmail.com> wrote:
[...]
> > Actually, one member of a shadow set will be designated
> > the master.  I believe this is used as the source during
> > shadow copies.  Otherwise, all members are treated as
> > equal.
>
> That is not the algorithm that I recall.  I've been out of the VMS biz
> for years though, so take what I say with a grain of salt.  

[...BIG SNIP...]

> The point I'm trying to make is that there isn't a single statically
> identified volume that is "the master".

I didn't mean to imply that the master was static, only that
at any given time, one member *is* designated the master,
and you can find that, e.g., with

$ mast = f$getdvi("dsaxxxx:","shdw_master_mbr")

Also note that since about v7.3-2, you can set the shadow
copy source member via,

$ set device/copy_source $1$dgaxxxx:

I never investigated whether the copy source becomes the
master (I doubt it), so my comment about the master being
the copy source is probably wrong, or at least outdated.

    -Ken