use 1 thread by default in purge (instead of 4)
use 1 thread by default in purge (instead of 4)

mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs