[Info-vax] NEW HBVS question

[Phillip Helbig undress to reply]

In article <qntepo$o2g$1 at gioia.aioe.org>,
helbig at asclothestro.multivax.de (Phillip Helbig (undress to reply))
writes: 

> In article <qnt564$1ad1$3 at gioia.aioe.org>,
> helbig at asclothestro.multivax.de (Phillip Helbig (undress to reply))
> writes: 
> 
> > > >Yes, I could have missed a minicopy.  I thought that if I shut down the 
> > > >entire cluster (properly or not), then the bitmaps used by minicopy 
> > > >would disappear, since they are only in RAM.  Or are they written to 
> > > >disk (at least in case of a proper shutdown)?
> > > 
> > > It's kind of hard to figure out from what you have posted. I suggest you troll
> > > through the OPERATOR.LOGs to see what shadowing has been up to since this
> > > instance of the cluster was created.
> > > 
> > > As goofy as shadowing can be at times, one thing I've never seen it get wrong
> > > is not doing copies/merges when it should. We'd know about that very quickly 
> > > since getting that wrong will show up rapidly as bizarrely corrupted data.
> > > 
> > > What do SHOW SHADOW and SHOW DEVICE say?
> > 
> > Back from holiday, cluster still OK with the new BA356 installed just 
> > before leaving.
> > 
> > As you say, SHADOWING rarely if ever gets it wrong.  Perhaps the 
> > minicopies on these relatively small disks were so quick that I didn't 
> > notice them.  I'll check the logs.
> 
> Yes, it was just too quick, just a few seconds.

OK, but still: The cluster was completely shut down, then the two
two-node shadow sets with members connected (local SCSI connection only)
to nodes A and B were mounted on nodes A and C while node B stayed down 
for another two hours.  When B booted, there were the minicopies.  But 
why not full copies?  True, there had been now WRITEs to these disks, 
but how did VMS know?

Do the bitmaps survive a cluster reboot (at least if the shutdown is 
clean and there is a DISMOUNT/POLICY=MINICOPY), i.e. are they written to 
disk somewhere?  If not, why minicopies and not full copies?