The NUFA ("Non Uniform File Access") is a variant of the DHT ("Distributed Hash Table") translator, intended for use with workloads that have a high locality of reference. Instead of placing new files pseudo-randomly, it places them on the same nodes where they are created so that future accesses can be made locally. For replicated volumes, this means that one copy will be local and others will be remote; the read-replica selection mechanisms will then favor the local copy for reads. For non-replicated volumes, the only copy will be local.
Use of NUFA is controlled by a volume option, as follows.
gluster volume set myvolume cluster.nufa on
This will cause the NUFA translator to be used wherever the DHT translator otherwise would be. The rest is all automatic.