Russell McMahon wrote :

> > An off-machine backup is the only way to properly
> > protect against loss of data, and it's not guaranteed
> > even then!
>
> Off machine, not in the same room, not in the same building,
> not in the same block, not in the same city, not ... .
> Not connected live most of the time.
> (Obvious, obvious, fire, large fire, volcano*,...)

For environmental hazars, might it be water, fire, vulcanos or
911-like stuff, you could just shadow your disks over a distance.
One bank in WTC had a mirror site off-Manhattan, and just asked
there people to go there instead and just continued there
banking operations. No downtime, no data restores and their
clients had access to theres data after some re-routing of the
datacom. Their system managers could actualy see how the
disks located in the WTC fell out of the shadowsets one-by-one...

The same when a bank in Paris had a major fire some years ago.
They had a complete mirror site on the other side of the river.
The data was safe, they just had to gather some desks and PC-
clients (but that was on a service contract, so no big deal).

Both used the builtin shadowing service in the OS (up to
about 150 miles disk shadowing supported with the plain
standard OS "out-of-the box"). No 3-part cludge...

That is how those issues should be handled.

Now, of course you have to *backup* your data anyway, to
protect agains other risks (OS or application errors). The
backup could be run against the shadowed data on the currently
non-operational system to not slow down the main system.

Anyway,
I'm sure they've never seen a "MPLAB Error 173" error either...
:-)

Regards,
Jan-Erik

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