Re: Adding a disk to a RAID array

<snip>
> With the second best scenario the second machine has a normal net
> address and the master machine has it blocked from the main network via
> IP Tables and the main network blocked from it. The only "transactions"
> made are through the second NIC with a special one address routing. Thus
> the second machine is up to date with the first and completely isolated
> from the main network. When the main machine goes down Elizabeth will
> have to hustle down to the vault and pull the main and side network
> cables from the main machine, setup the second machine with a special
> IPTables setup to NAT the main machine's address to its own so that it
> looks like the main machine to the main network. Then plug the main
> network into the secondary machine. This should take no more than five
> minutes plus "travel time". So patient safety is not compromised as
> little as possible while the Feds are satisfied with the security, since
> both machines are on the same software and same setup except for their
> network address. IPTables address translation takes care of that issue
> when the second machine needs to go online.

There is another way, that's similar. Almost realtime backup on the second
machine via a direct link crossover cable and rsync with a perl script to
check the source machine's NET_IF to see if it's live. If it's not, it
assumes the IP address of the source machine and carries on with little
interruption in services. Both machines need to be dual-homed, and both
need to be connected to the public router, although the NET_IF of the
second machine is down until needed. It's not difficult to do in
comparison to other scenarios (clustering, etc) and the TCO is fairly low
in the grand scheme of things.

Of course, all this is moot. Elizabeth has the beancounters breathing down
her neck to limit expenditures to nothing while the feds and the admin
staff are demanding a combination of fort knox/champagne service.
Something, somewhere has to give, and I hope it won't be her.

Elizabeth, you need a second machine if downtime is not an option. Simple
as that, the beancounters simply have to give it up. Without this
breathing room, there is no way to create the extra space with what
hardware resources you've got.

Good luck with it.
-- 
Keith Mastin
BeechTree Information Technology Services Inc.
Toronto, Canada
(416)696 6070