Rather than limp along with a broken SLOW channel system, I fixed it so that the EDCU files made during the RCG build actually get used and added to the channel list (and thereby available in DV and trends).
I first started by adding all of the EDCU files. This completely fails; daqd just doesn't start and gives some weird exceptions.
So I removed a bunch of them and it runs OK now with ~15000 channels. Previously we had ~1500 slow channels.
An in-between config tonight had ~58000 channels and was also running fine, but the connection to the FB would time out when using DV after several minutes. Possibly we can fix this by adding some more RAM to the FB (the DAQD process uses up 45% of the CPU and 39% of the 8 GB of RAM).
Another issue in getting this to work was that there were a bunch of channel name conflicts between the old C0EDCU.ini and the sub-system EDCU files that I was trying to add. I went through by hand and deleted all of the duplicates from the old file. The new frame files are 80 MB, the old ones were 66 MB.
I hope that /frames doesn't become full - not sure how that is wiped...