b) what's the general feeling as to production worthiness of the xen3 stuff? As stable as xen2 (which is working just great for me, and I use it for a number of dom0's and dozens of domU's of different shapes and forms)?
I have been using a NetBSD Xen 2 Dom 0/ Multiple Dom U setup for around 10 months at home with absolutely no problems what so ever. I've been contemplating upgrading to Xen 3, but have been waiting to hear a few success stories before making the leap. Elsewhere I run a Xen 3.0.2-2 Linux Dom-0 with around 10 different Dom-U's covering Linux, NetBSD and FreeBSD. One of my NetBSD dom-U's on that Linux Xen 3 dom-0 has been running "production" traffic and has an uptime of 125 days, with just 1 problem - an apparent random networking lockup that was resolved with a simple ifconfig bounce. So from my experience certainly NetBSD Xen 3 Dom-U is stable. The thing I miss most in my home Xen 2 is the xm top command available in Xen 3.