We've been looking at some type of domain/DNS failover. But for us,  I'd like the other VPS to be at least in a different part of the city (if not country). Also, the site that does the failover management should be in yet another location. I suppose IP failover to a different box is of some value in the event that a box has problems, but would it help in common scenarios such as (a) network routes down or (b) power failure?

- Sandy


On Mon, Jan 17, 2011 at 11:02 PM, Andy Smith <andy@bitfolk.com> wrote:
Hello,

If you have two VPSes, it's relatively simple to have an IP address
that flips between them.

So say for example you have vps-a on IP 212.13.194.32 and vps-b on
212.13.195.43, and you also have a third IP address 212.13.195.20
that starts off routed to vps-a. You put a web server listening on
212.13.195.20 which hosts some important pictures of your cat which
require high availability.

Some mishap befalls your vps-a, like your web server dies or the
actual hardware it's on dies or something. vps-b notices that vps-a
isn't responding any more and so does something to flip
212.13.195.20 over to itself and continue serving your cat gallery
with many 9's of availability. None of your cat's admirers notice
that one of your VPSes died.

Right now if you buy two VPSes you can already do all of that except
flip the IP address over between them. You need BitFolk's help to
flip an IP address from one VPS to another because normally you
can't ARP for an IP address you don't have routed to you. If you did
bring up 212.13.195.20 on vps-b, all the packets would still end up
going to vps-a.

We can make it so that you can do something to flip that IP to one of
your other VPSes. You take care of all the other details. There
would most likely be no charge for this beyond you having to have
two VPSes.

Is there any interest?

Cheers,
Andy

PS I don't want to get into the idea of failing over an entire VPS
  at the moment, nor of automatically migrating a single VPS
  between hosts. Both are certainly doable, but the complications
  of shared storage and/or reserving unsold resources on other
  hosts so that VPSes can be failed over to them are too much. Use
  Amazon EC2 or something?

  But if you have 2+ VPSes, flipping IP addresses around between
  them is quite simple.

--
http://bitfolk.com/ -- No-nonsense VPS hosting

"The electric guitar - like making love - is much improved by a little
 feedback, completely ruined by too much." -- The League Against Tedium

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