After configuring DFS Replication, you get this warning:
To size the staging folder quota large enough to prevent replication from slowing or stopping, you must take into account the size of the files to be replicated.
Basically this is just telling you to adjust the staging folder quota size to match the size of the data you intend to replicate at any one time (data size divided by the speed of your internet connection – or some similar algorithm).
If you’re not replicating much data with DFSR or you’re not bothered about the performance of DSFR, it’s probably safe to ignore this message.