Hi Voiding,
You satellite systems need to send the data to SLD. IF it is ABAP then you need to configure your SLD details in RZ70. There is a job SLD_DATA_SUPPLIER which runs in your satellite system and send the data to SLD.
When you configure LMDB in SOLMAN_SETUP.. The intial sync will take too much time which gets the information of all the techinical systems from SLD. After that in your solman there is a delta LMDB job runs periodically which gets the changes of SLD information LMDB.
SMSY was a old view which was used earlier to solman 7.1 . Here you cant change anything. Most of the things you have to manage in LMDB.
in layman language, LMDB is similar to SMSY but got new features and concept is lil bit different.
Thanks,
Jagadish.