per-channel data bytes lookback limit
This is needed to keep the stored data from blowing up when the lookback is set too long. doing it per-channel will allow longer lookback for channels with slower data rate.
For instance, a 300MB limit per channel would allow for ~10 minutes of fast 16kHz data and ~1 week of 16Hz data. Still have to worry about the overhead of displaying that much data, though, which is more than 9.4e9 points.
Edited by Jameson Rollins