Oh yeah. I know. I would expect for some-to-many minor things (like the TCP bug you mentioned), this wouldn't be an insane way to do a hot upgrade. Guess one would need to make a close study of the diffs.
Regardless, I mentioned the fact that this isn't a good idea for any novice who might stumble across this comment months or years hence and get the wrong idea. :)
> ...maybe I should just run CARP myself on the hosts...
Oh, CARP is so cool. It's a bit of a pity that ucarp doesn't support IPv6. But, how does CARP replace a load balancer? Isn't it used for single host availability, or is my understanding too narrow?
I have two servers, if I get two carpable ips, and may each server primary on one, and put them both in DNS, I have load balancing and failover. If I just use one IP, at least I have failover, anyway I need each server to be able to handle full load, so I could have hot-warm instead of hot-hot.
(with more than two servers, need to figure something else out, probably two boxes running a simple load balancing in front of the rest of the cluster.
>> I have to use DNS for load balancing [because the load balancers fall over often].
>Oh lord. That's a terrible situation to be in.
It's not terrible, it's just not great. Our hosting environment is generally very reliable, so if I don't screw things up, my systems won't fall over. It's just their loadbalancers are crap, the suggested upgrade path was run a load balancer in a VM appliance; which seems like maybe I should just run CARP myself on the hosts (or something), instead, and skip a layer, but I'll probably never get around to that, because it doesn't come up that often :)