I upgraded one of my Debian servers to 6.0 (squeeze) today. This system is currently not that critical (it won't kill me if I can't watch TV ^_^) but it is about to become my new mail server, so this seemed like an appropriate time to do the upgrade.
The upgrade went smoothly but I miss the the good old days when a Debian upgrade consisted of three steps: change sources.list, run "apt-get update", and run "apt-get dist-upgrade". Although the upgrade completed successfully, there are still a few bits to be ironed out.
One of the problems is that the new dependency based initscript system (insserv) causes the NFS export to fail, because the DNS server has not started yet. The old System-V-like system never had this problem. The easiest solution is to use IP address in the /etc/exports file, but hard coding IPs seems backwards to me, so it looks like I'll be digging into the mysteries of insserv.
This is OK, since I have have a custom initscript which also has to be integrated with insserv, so learning it was unavoidable. The mildly annoying part is that insserv is already slated to be replaced in the next Debian release. It says a lot about the old, equally broken but well understood, System-V style startup which had been around since forever. Ah, progress!