Hi Thomas,
I don't think I have seen compaction ever being faster.
For me, tables with small values usually are around 5 MB/s with a single
compaction. With larger blobs (few KB per blob) I have seen 16MB/s. Both
with "nodetool setcompactionthroughput 0".
I don't think its disk related either. I
I can't say for sure, because I haven't measured it, but I've seen a
combination of readahead + large chunk size with compression cause serious
issues with read amplification, although I'm not sure if or how it would
apply here. Likely depends on the size of your partitions and the
fragmentation o