Facility wide DR/Continuity

Brandon Galbraith brandon.galbraith at gmail.com
Wed Jun 3 17:53:17 UTC 2009

On Wed, Jun 3, 2009 at 12:47 PM, Bill Woodcock <woody at pch.net> wrote:

>      On Wed, 3 Jun 2009, Drew Weaver wrote:
>    > Should the additional sites be connected to the primary site
>    > (and/or the Internet directly)?
> Yes, because any out-of-band synchronization method between the servers at
> the production site and the servers at the DR site is likely to be more
> difficult to manage.  You could do UUCP over a serial line, but...
>    > What is the best way to handle the routing? Obviously two devices
>    > cannot occupy the same IP address at the same time, so how do you
>    > provide that instant 'cut-over'?
> This is one of the only instances in which I like NATs.  Set up a NAT
> between the two sites to do static 1-to-1 mapping of each site into a
> different range for the other, so that the DR servers have the same IP
> addresses as their production masters, but have a different IP address to
> synchronize with.

Or you use RFC1918 address space at each location, and NAT each side between
public anycasted space and your private IP space. Prevents internal IP
conflicts, having to deal with site to site NAT, etc.


Brandon Galbraith
Mobile: 630.400.6992
FNAL: 630.840.2141

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