After some discussion at last week's 40m meeting, I increased the frequency of daqd trying to write out minute trends from hourly to every two hours.
This has eliminated the hourly crashes. daqd still crashes sometimes, but only a few times per day.
However, looking at the oplev summary pages that actually use the minute trends, it looks like they're only sporadically getting succesfully written out.
Also, I was having a lot of problems with the frontends' EPICS processes dying when I would try to update the SDF table. I rebuilt all of the frontends with RCG 2.9.6, which differs from the 2.9.4 that we had been running by SDF bugfixes and an RMS calculation bugfix. The SDF procedures are much more stable now.
I have not yet discovered anything broken by this chage, and the tests I made for the last upgrade were all fine; last weeks tiny DRFPMI lock was achieved after this change.