Another
MDSPlus concern is the data store itself. It proved challenging
to maintain usability under the current permission system
that MDSPlus employs. Instead, DCPS will use a secondary
data server hidden behind the main MDSPlus host that serves
data for all of NSTX-U. This secondary server provides two
functions: extra security due to restricted permissions and data
hiding, and contingency against network failures, as the main
DCPS program has a direct patch cable link on a secondary
Ethernet interface to the data server itself. This dual path
access ensures that during an actual test shot, any transient
network issues will not affect the real-time operation of DCPS
and thus NSTX-U.