robocopy source: destination: /MIR /R:1 /W:1 /MT:32 /SEC

/MIR – MIRror a directory tree
/SEC – copy files with SECurity
/R:1 – number of Retries on failed copies
/W:1 – Wait time between retries
/MT:32 – Do multi-threaded copies with n threads (default 8)