RHEL 7.4, heavy workload(s) and SWAP usage
If you have 8GB swap, 256 GB physical memory and swappiness=1, with memory usage nearing 72Gb, it's acceptable to swap operations almost 700MB (72GB * 1%), then the 100MB swap usage that you had seen is pretty normal.

Be sure that your 1TB daily data load doesn't exhaust your physical memory and you can change swappiness to 0 without side effects.

But do you have a quite low swap rate in your setup. Do you really need to avoid swap?