[Info-vax] Current VMS engineering quality, was: Re: What's VMS up to these
John Wallace
johnwallace4 at yahoo.co.uk
Fri Mar 16 05:17:28 EDT 2012
On Mar 16, 8:31 am, Paul Sture <p... at sture.ch> wrote:
> On Fri, 16 Mar 2012 05:19:22 +0100, Michael Kraemer wrote:
> > Paul Sture schrieb:
>
> >> There were a couple of other problems here. When twenty odd
> >> workstations were trying to reboot, when the network came back they all
> >> did it more or less at once.
>
> > Yep, rather messy.
> > Plus, when the network still had persistent/intermittent problems, the
> > whole configuration remained dead in the water.
>
> We didn't usually have such a long outage. Sometimes it hit the PCs
> rather than the VMS systems, and in these cases we could carry on
> working, but the PC only folks were out of luck. With a bit of luck, you
> could save any work in progress to your local PC disk, but that was not
> always the case.
>
> >> Until I changed the workstations to use Dump Off System Disk (DOSD),
> >> the server system disk would go into a full shadow merge (or was it
> >> shadow copy?). This caused further problems:
>
> >> a) the boot times were exceptionally long b) some part of DECnet Phase
> >> V could time out and you'd have to reboot the workstation later to
> >> recover from this
>
> > I don't know if this would have helped in the cases I experienced. But
> > I'm rather sure the responsible VMS experts would have tried it, if
> > possible. Too embarrassing, a VMS cluster unavailable for hours.
>
> It definitely helped us, but ISTR having more than one go at
> implementing DOSD. I finally acquired some definitive instructions
> amd those worked fine. I was the only one on our team to think about
> this solution, so maybe there were many other system managers out there
> who didn't know about it.
>
> Prior to getting DOSD working we would drop the system disk non-master
> shadow set until the whole cluster was up. Not an ideal workaround but
> it did the job.
>
> --
> Paul Sture
The shadowed boot device vs DOSD scenario is an example of the need
for real experience and expertise in cases like this. The rest of it
mostly hopefully works out of the box, give or take, but there are
sometimes details hiding in dark corners which will get you if you are
unaware.
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