DST in OES 2018 SP3 has been modified for bug fixes, DST provides the following enhancements and changes in OES 2018 SP3
A configurable option called Replicate Primary Tree to Shadow is by default set to 1, so when the existing NSS volumes are configured as primary volume for DST, the primary volume directory tree structure will get replicated to the shadow volume directory tree. See Section 7.1, Replicating Branches of the Primary File Tree in the Secondary File Tree