Asterisk Clustering / DUNDi

I currently have a location to setup within my company that is going to require more than one server (we’re looking at 4, currently). The multiple servers are both for handling the call load AND for redundancy. I’ve been doing a substantial amount of reading and research into ways to do this. I could use openser/ser, but I really am not a fan of using an additional application and having the phones register to it instead of Asterisk. I would also need to account for two of those machines being clustered in case one failed (no single point of failure is acceptable), so that is extra complexity and hardware. Instead, I’ve been looking at using DUNDi; but I have three questions:

  1. All of the examples I see show using one DUNDi lookup server, which eases management, but again presents a single point of failure. Aside from the added maintenance needs when changes arise, is there any other problem with not having a dedicated DUNDi lookup server?

  2. A listed “pitfall” is having problems if one phone parks a call on server1 and wants to have a phone on server2 access the call. Is it true that they would not be able to execute this transfer? I find this surprising since that would be a pretty major shortcoming. If the phone you are transferring to is not on the local server, would it not execute a lookup and find where it is, then transfer the call?

  3. With this setup it still appears that the phones would have to be statically assigned to each PBX to keep the load balanced, and then use the others for failover. Is there some way of dynamically assigning each phone registration to a server randomly? I’ve heard there can be issues with using a round-robin DNS approach.

Any and all help is MUCH appreciated.