Thanks, but not true in my case. I actually wasn't asking if it was required, as I already know that it is - I asked if anyone had installed apcupsd on their S2 & what their experience was with it - but thanks for your input.
It looks like you are looking for a project to do on your miner.
In that case the sensible task is to modify the flash image:
1) boot with all file systems read-only
2) remount the fs read-write before the reconfiguration
3) remount the fs back to read-only after executing the configuration change
4) reconfigure syslogd (and other daemons) for logging to an external log concentrator
5) run the mining controller/concentrator on the UPS
Not only your flash storage will never be get corrupted but also you'll greatly increase its durability.
Obviously on Bitcointalk there always will be a sub-segment that treat coin mining as a status symbol.
For those I always advocate to look up the appropriate solution developed for audiophiles.
Edit: apcupsd and other UPS-communicating software only make technical sense when running on a server-grade hardware with error-correcting memory and the related processor circuitry fully supporting machine-check exceptions and recovery. Unless you change the controller in your miner that isn't the case. You'll just alter the failure modes and somewhat skew the probabilities of failures in your mining farm.
Edit2: I don't want to bump the thread: If you are really into running a mining farm on the UPS (e.g. you've already paid for it and cannot change the setup) then the proper tool to run is
http://en.wikipedia.org/wiki/Network_UPS_Tools , which have both APC interface as well as support multiple devices per UPS and multiple UPS-es. N.U.T. also supports trivial UPS-ing via the cli: ssh/rlogin/telnet to each device and execute shutdown/poweroff/halt/telinit/whatever-else.
