I want to migrate my plesk server. The easiest and most fast solution is to use the migrate wizard; move the content from one machine to the other. After the migration the content must be accessible on exactly the same ip-address. Therefore I need to have two boxes, both connected to the same network and with shared (the same) ip addresses. See the situation below:

Server01:

eth0 xx.xx.xx.100 (connected to the internet as remote ipaddress)
eth0:0 xx.xx.xx.200 (connected to the internet and serves content)

Server02:

eth0 xx.xx.xx.150 (connected to the internet)
eth0:0 xx.xx.xx.200 (must be offline! will serve migrated content)

The xx.xx.xx.200 on the Server02 must be offline and should not conflict with the xx.xx.xx.100. Bringing down eth0:0 is not an option! How do I do this?

This could only be accomplished with Multicast addressing, which is going to be tough. This is impossible using standard ip addressing. When the router sends out the ARP request asking for who has the IP address, it's going to stick with the first that responds and put it in cache. Thereafter it'll only send packets to that physical device. Unless you could spoof MAC addresses, but still the application would need to be aware of this. If you're migrating, can't you take it down for the amount of time it'll take to move data? And bring it back up on the new box w/ the same IP?

Just a suggestion, because I have very limited understanding of what I'm talking about, but how about high availability linux? It might require the use of a 3rd machine, tho (like I said, I have zero expertise in the matter). The way I understand the basics, in one server can be used as a backup for serveral others, when one goes offline, it seamlessly fills in with no noticeable diff as far as clients are concerned.

Thanks but I fixed it with a dummy driver (modprobe dummy).