[Info-vax] FREESPADRIFT

[Paul Sture]

On 2016-06-17, David Froble <davef at tsoft-inc.com> wrote:
> Paul Sture wrote:

<snip>

>> 
>> Footnote: some concrete figures for money lost by extended downtime
>> came out of that incident and management was not afraid to invest
>> in beefing up their disaster recovery capabilities.
>> 
>
> Too bad that it appears to be a case of closing the barn doors after
> the horses are out ....

Q: Why close the door after the horse has bolted?
A: To stop the chickens coming home to roost!

>
>:-)
>
> But, better late than never ....

Actually this was more a case of critical systems being disaster
tolerant (DT versus DR). I don't think anyone had thought of the case
where a whole building was out.

Initial solution: move selected systems to another building; just across
the road would do for starters, but leave you vulnerable to a street
level failure.  Fortunately this customer was large enough to have
existing data centres in different locations.

This is where the then recent arrival of Fibrechannel opened up
possibilities - you could put 'local' disks in another building.

Longer term solution: build another data centre in another location
and add a third data centre later.

-- 
There are two hard things in computer science, and they are cache invalidation,
naming, and off-by-one errors.