Hi,
Normally dsm.opt carries the server name and
dsm.sys carries the entire information with regards to the server name. Additionally u can also have as many as server name. which has to be represented separtely as separate file dsm.opt. for each of the server name.
Simply to explain , u can have many dsm.opt but only one dsm.sys u can have. the detailed finformation of each server should be entered ins separate paragraphs.
The moment you try to open the dsmj, initially it will verify the dsm.opt in which the node is currently associated. after then it will look on to the corresponding information of the server name in dsm.sys.
so its must to have a dsm.opt and dsm.sys to gether.. its best practice to have both of the file in the same location/directory.